preferred1.htm

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM N-Q

QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED
MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number 811- 21287

John Hancock Preferred Income Fund III
(Exact name of registrant as specified in charter)

 601 Congress Street, Boston, Massachusetts 02210
(Address of principal executive offices) (Zip code)

 Alfred E. Ouellette, Senior Attorney and Assistant Secretary

601 Congress Street

Boston, Massachusetts 02210


(Name and address of agent for service)

Registrant's telephone number, including area code: 617-663-4324

Date of fiscal year end:  May 31 
Date of reporting period:  August 31, 2005 


ITEM 1. SCHEDULE OF INVESTMENTS




John Hancock           
Preferred Income Fund III         
Securities owned by the Fund on         
August 31, 2005 (unaudited)           
 
  Interest  Maturity  Credit  Par value   
Issuer, description  rate (%)  date  rating (A)  ($000)  Value 
Bonds 6.84%          $75,634,804 
(Cost $71,398,157)           
 

Automobile Manufacturers 0.20%
 
        2,202,981 

Ford Motor Co.,           
Note  7.450  07-16-31  BB+  2,755  2,202,981 

Consumer Finance 0.26%
 
        2,775,444 

General Motors Acceptance Corp.,           
Bond  8.000  11-01-31  BB  3,000  2,775,444 

Electric Utilities 3.66%
 
        40,529,483 

Black Hills Corp.,           
Note  6.500  05-15-13  BBB-  15,000  15,978,690 
DPL, Inc., Sr Note           
Sr Note  6.875  09-01-11  BB-  5,036  5,514,420 
Entergy Gulf States, Inc.,           
1st Mtg Bond  6.200  07-01-33  BBB+  15,000  15,388,305 
Kentucky Power Co.,           
Sr Note, Ser D  5.625  12-01-32  BBB  3,565  3,648,068 

Integrated Oil & Gas 0.54%
 
        5,967,965 

Amerada Hess Corp.,           
Note  7.125  03-15-33  BBB-  5,000  5,967,965 

Multi-Utilities & Unregulated Power
  1.11% 
      12,270,878 

DTE Energy Co.,           
Sr Note  6.375  04-15-33  BBB-  7,500  8,189,415 
TECO Energy, Inc.,           
Note  7.000  05-01-12  BB  3,810  4,081,463 

Oil & Gas Refining, Marketing & Transportation 1.07%
 
      11,888,053 

Valero Energy Corp.,           
Note  7.500  04-15-32  BBB-  9,500  11,888,053 
      Credit  Par value   
Issuer, description, maturity date      rating (A)  ($000)  Value 
Capital preferred securities  8.03%        $88,854,979 
(Cost $88,538,386)           
 
Diversified Banks 3.20%          35,386,700 

Credit Agricole Preferred Funding Trust,         
7.00%, 01-29-49      A  9,000  9,416,700 
Lloyds TSB Bank Plc, 6.90%, 11-29-49 (United         
Kingdom)      A+  25,000  25,970,000 

Page 1


John Hancock         
Preferred Income Fund III       
Securities owned by the Fund on       
August 31, 2005 (unaudited)       
 
Electric Utilities 0.69%      7,625,625 

DPL Capital Trust II, 8.125%, 09-01-31  B+  6,225  7,625,625 


Gas Utilities 0.53%
 
      5,809,767 

KN Capital Trust III, 7.63%, 04-15-28  BB+  4,960  5,809,767 

Integrated Telecommunication Services 1.45%
 
    16,033,839 

TCI Communications Financing Trust III,       
9.65%, 03-31-27    BBB-  14,210  16,033,839 

Investment Banking & Brokerage 0.93%
 
    10,300,000 

HBOS Capital Funding L.P., 6.85%, 03-29-49       
(United Kingdom)    A  10,000  10,300,000 

Multi-Utilities & Unregulated Power 0.90%
 
    10,009,165 

Dominion Resources Capital Trust I, 7.83%,       
12-01-27    BBB-  9,097  10,009,165 

Other Diversified Financial Services 0.33%
 
    3,689,883 

JPM Capital Trust I, 7.54%, 01-15-27  A-  3,447  3,689,883 
Issuer      Shares  Value 
Common stocks  3.17%      $35,058,946 
(Cost $34,098,183)         
 
Electric Utilities 1.35%      14,930,274 

American Electric Power Co., Inc.    294,378  10,944,974 
Scottish Power Plc, American Depositary       
Receipt (United Kingdom)    110,000  3,985,300 

Multi-Utilities & Unregulated Power 1.82%
 
    20,128,672 

CH Energy Group, Inc.      20,600  990,860 
DTE Energy Co.      304,016  13,914,812 
TECO Energy, Inc.      300,000  5,223,000 
    Credit     
Issuer, description    rating (A)  Shares  Value 
Preferred stocks  81.60%      $902,671,717 
(Cost $883,840,154)         
 

Agricultural Products
  1.52% 
    16,830,937 

Ocean Spray Cranberries, Inc., 6.25%, Ser A       
(S)    BB+  195,000  16,830,937 

Asset Management & Custody Banks 0.39%
 
    4,277,765 

BNY Capital V, 5.95%, Ser F  A-  170,361  4,277,765 

Page 2


John Hancock       
 
Preferred Income Fund III       
 
Securities owned by the Fund on       
 
August 31, 2005 (unaudited)       
 
Automobile Manufacturers 2.66%      29,459,909 

Ford Motor Co., 7.50%  BB+  771,385  16,569,350 
General Motors Corp., 7.25%, Ser 07-15-41  BB  55,641  1,061,630 
General Motors Corp., 7.375%, Ser 05-15-48  Ba2  593,194  11,383,393 
General Motors Corp., 7.375%, Ser 10-01-51  BB  22,100  445,536 
 
Broadcasting & Cable TV 0.35%      3,884,387 

Shaw Communications, Inc., 8.50% (Canada)  B+  150,850  3,884,387 
 
Consumer Finance 2.40%      26,542,471 

CIT Group, Inc., 6.35%, Ser A  BBB+  70,000  1,808,100 
Ford Motor Credit Co., 7.60%  Baa3  25,000  542,000 
Household Finance Corp., 6.875%  A  636,118  16,609,041 
HSBC Finance Corp., 6.36%, Depositary Shares,       
Ser B  BBB+  250,000  6,477,500 
SLM Corp., 6.97%, Ser A  BBB+  19,800  1,105,830 
 
Diversified Banks 6.23%      68,953,783 

BAC Capital Trust II, 7.00%  A  94,600  2,445,410 
BAC Capital Trust III, 7.00%  A  22,000  571,340 
BAC Capital Trust IV, 5.875%  A  406,400  10,115,296 
Royal Bank of Scotland Group Plc, 5.75%,       
Ser L (United Kingdom)  A  960,000  23,750,400 
Santander Finance Preferred S.A. Unipersonal,       
6.41%, Ser 1 (Spain)  BBB+  100,000  2,650,000 
USB Capital IV, 7.35%  A-  59,100  1,523,007 
USB Capital V, 7.25%  A-  60,700  1,589,126 
Wachovia Preferred Funding Corp., 7.25%, Ser A  A-  674,800  19,420,744 
Wells Fargo Capital Trust IV, 7.00%  A  187,800  4,785,144 
Wells Fargo Capital Trust VII, 5.85%  A  84,200  2,103,316 
 
Electric Utilities 12.89%      142,628,898 

Cleveland Electric Financing Trust I, 9.00%  BB  27,400  731,580 
Consolidated Edison, Inc., $5.00, Ser A  BBB+  30,000  2,730,000 
Consolidated Edison, Inc., 7.25%  A-  56,000  1,472,800 
Entergy Mississippi, Inc., 7.25%  A-  63,918  1,645,249 
FPC Capital I, 7.10%, Ser A  BB+  684,200  17,187,104 
FPL Group Capital Trust I, 5.875%  BBB+  470,000  11,858,100 
FPL Group, Inc., 8.00%, Conv  A-  112,000  7,228,480 
Georgia Power Capital Trust V, 7.125%  BBB+  132,200  3,455,708 
Georgia Power Co., 6.00%, Ser R  A  730,000  18,556,600 
Great Plains Energy, Inc., 8.00%, Conv  BBB-  639,300  18,140,137 
HECO Capital Trust III, 6.50%  BBB-  130,000  3,445,000 
Interstate Power & Light Co., 7.10%, Ser C  BBB-  354,900  9,830,730 
Interstate Power & Light Co., 8.375%, Ser B  BBB-  54,500  1,798,500 
Monongahela Power Co., $7.73, Ser L  B  65,557  6,588,478 
Northern States Power Co., 8.00%  BBB-  74,550  1,997,940 
NVP Capital I, 8.20%, Ser A  CCC+  56,300  1,431,146 
NVP Capital III, 7.75%  CCC+  379,705  9,629,319 
Sierra Pacific Power Co., 7.80%, Ser 1 (Class       
A)  CCC+  73,507  1,856,052 
TXU Corp., 8.125%, Conv  Ba1  170,000  13,200,500 
Virginia Power Capital Trust, 7.375%  BBB-  376,500  9,845,475 

Page 3


John Hancock       
 
Preferred Income Fund III       
 
Securities owned by the Fund on       
 
August 31, 2005 (unaudited)       
 
 
Gas Utilities 3.12%      34,460,919 

Laclede Capital Trust I, 7.70%  BBB+  63,300  1,677,450 
SEMCO Capital Trust I, 10.25%  B-  45,376  1,140,299 
Southern Union Co., 7.55%  BB+  350,000  9,485,000 
Southwest Gas Capital II, 7.70%  BB  810,250  21,552,650 
Vectren Utillity Holdings, Inc., 7.25%  A-  23,200  605,520 
 
Hotels, Resorts & Cruise Lines 0.28%      3,064,624 

Hilton Hotels Corp., 8.00%  BBB-  118,600  3,064,624 
 
Integrated Oil & Gas 1.41%      15,575,000 

Coastal Finance I, 8.375%  CCC  623,000  15,575,000 
 
Integrated Telecommunication Services 2.34%      25,854,437 

Telephone & Data Systems, Inc., 6.625%  A-  437,900  11,275,925 
Telephone & Data Systems, Inc., 7.60%, Ser A  A-  415,576  10,809,132 
Verizon New England, Inc., 7.00%, Ser B  A3  146,100  3,769,380 
 
Investment Banking & Brokerage 8.93%      98,810,733 

Fleet Capital Trust VII, 7.20%  A  61,604  1,600,472 
Fleet Capital Trust IX, 6.00%  A  469,200  11,786,304 
Lehman Brothers Holdings Capital Trust III,       
6.375%, Ser K  BBB+  793,400  20,549,060 
Lehman Brothers Holdings, Inc., 5.67%,       
Depositary Shares, Ser D  BBB+  142,500  7,160,625 
Merrill Lynch Preferred Capital Trust III,       
7.00%  A-  417,017  10,984,228 
Merrill Lynch Preferred Capital Trust IV,       
7.12%  A-  232,700  6,173,531 
Merrill Lynch Preferred Capital Trust V, 7.28%  A-  373,700  9,962,842 
Morgan Stanley Capital Trust III, 6.25%  A-  764,025  19,222,869 
Morgan Stanley Capital Trust IV, 6.25%  A-  393,925  9,970,242 
Morgan Stanley Capital Trust V, 5.75%  A1  57,400  1,400,560 
 
Life & Health Insurance 2.14%      23,689,986 

Lincoln National Capital VI, 6.75%, Ser F  BBB  304,000  7,995,200 
Phoenix Cos., Inc. (The), 7.45%  BBB  387,849  10,080,196 
PLC Capital Trust IV, 7.25%  BBB+  120,600  3,177,810 
PLC Capital Trust V, 6.125%  BBB+  66,000  1,658,580 
Prudential Plc, 6.50% (United Kingdom)  A  30,000  778,200 
 
Multi-Line Insurance 5.88%      65,083,017 

AEGON N.V., 6.375% (Netherlands)  A-  135,000  3,491,100 
ING Groep N.V., 7.05% (Netherlands)  A  603,970  15,799,855 
ING Groep N.V., 7.20% (Netherlands)  A  641,000  16,839,070 
MetLife, Inc., 6.375%, Ser B, Conv  BBB+  11,680  322,485 
MetLife, Inc., 6.50%, Ser B  BBB  1,108,850  28,630,507 

Page 4


John Hancock       
 
Preferred Income Fund III       
 
Securities owned by the Fund on       
 
August 31, 2005 (unaudited)       
 
Multi-Utilities & Unregulated Power 8.46%      93,610,157 

Aquila, Inc., 7.875%  B2  218,707  5,480,797 
Avista Corp., $6.95, Ser K  BB-  147,176  15,122,334 
BGE Capital Trust II, 6.20%  BBB-  592,728  15,114,564 
Consumers Energy Co. Financing IV, 9.00%  Ba2  189,700  4,951,170 
DTE Energy Trust I, 7.80%  BB+  106,500  2,783,910 
Energy East Capital Trust I, 8.25%  BBB-  179,900  4,654,013 
Enterprise Capital Trust I, 7.44%, Ser A  BB+  68,200  1,731,598 
Enterprise Capital Trust III, 7.25%, Ser C  BB+  104,100  2,648,304 
ONEOK, Inc., 8.50%, Conv  BBB+  197,600  8,107,528 
PSEG Funding Trust II, 8.75%  BB+  462,275  12,670,958 
Public Service Electric & Gas Co., 5.05%,       
Ser D  BB+  30,000  2,670,000 
Public Service Enterprise Group, Inc.,       
10.25%, Conv  BBB-  105,600  8,494,464 
Puget Sound Energy Capital Trust II, 8.40%  BB  185,600  4,810,752 
TECO Capital Trust I, 8.50%  B  171,700  4,369,765 
 
Oil & Gas Exploration & Production 3.95%      43,631,561 

Anadarko Petroleum Corp., 5.46%, Depositary       
Shares, Ser B  BBB-  24,600  2,440,782 
Apache Corp., 5.68%, Depositary Shares, Ser B  BBB  27,500  2,819,611 
Devon Energy Corp., 6.49%, Ser A  BB+  25,250  2,648,094 
Nexen, Inc., 7.35% (Canada)  BB+  1,360,879  35,723,074 
 
Other Diversified Financial Services 9.50%      105,124,240 

ABN AMRO Capital Funding Trust V, 5.90%  A  867,400  21,685,000 
ABN AMRO Capital Funding Trust VI, 6.25%  A  400,000  10,544,000 
Citigroup Capital VII, 7.125%  A  30,042  768,174 
Citigroup Capital VIII, 6.95%  A  220,200  5,696,574 
Citigroup Capital IX, 6.00%  A  384,700  9,682,899 
Citigroup Capital X, 6.10%  A  720,000  18,309,600 
General Electric Capital Corp., 5.875%  AAA  325,930  8,294,918 
General Electric Capital Corp., 6.10%  AAA  94,747  2,443,525 
JPMorgan Chase Capital XI, 5.875%, Ser K  A-  1,030,000  25,544,000 
JPMorgan Chase Capital XIV, 6.20%, Ser N  A-  25,000  629,750 
JPMorgan Chase Capital XVI, 6.35%  A-  60,000  1,525,800 
 
Real Estate Investment Trusts 4.91%      54,318,545 

Duke Realty Corp., 6.50%, Depositary Shares,       
Ser K  BBB  145,000  3,640,950 
Duke Realty Corp., 6.60%, Depositary Shares,       
Ser L  BBB  103,500  2,612,340 
Duke Realty Corp., 6.625%, Depositary Shares,       
Ser J  BBB  638,100  16,118,406 
Kimco Realty Co., 6.65%, Depositary Shares,       
Ser F  BBB+  384,750  9,922,702 
Public Storage, Inc., 6.18%, Depositary       
Shares, Ser D  BBB+  20,000  484,600 
Public Storage, Inc., 6.50%, Depositary       
Shares, Ser W  BBB+  450,000  11,385,000 
Public Storage, Inc., 7.50%, Depositary       
Shares, Ser V  BBB+  184,530  4,862,366 

Page 5


John Hancock             
Preferred Income Fund III           
Securities owned by the Fund on           
August 31, 2005 (unaudited)             
 
Public Storage, Inc., 7.625%, Depositary             
Shares, Ser T        BBB+  25,500  668,100 
Public Storage, Inc., 8.00%, Depositary             
Shares, Ser R        BBB+  177,100  4,624,081 

Regional Banks 2.49%
 
          27,479,462 

National Commerce Capital Trust II, 7.70%      A-  86,800  2,279,368 
PFGI Capital Corp., 7.75%        A-  926,900  25,200,094 

Reinsurance 0.28%
 
          3,067,200 

RenaissanceRe Holdings Ltd., 6.08%, Ser C           
(Bermuda)        BBB+  127,800  3,067,200 

Thrifts & Mortgage Finance 1.18%
 
          13,072,314 

Abbey National Plc, 7.25% (United Kingdom)      A-  163,265  4,204,074 
Abbey National Plc, 7.375% (United Kingdom)      A-  339,000  8,868,240 

Wireless Telecommunication Services
  0.29% 
        3,251,372 

United States Cellular, 7.50%        A-  119,800  3,251,372 
    Interest  Maturity  Credit  Par value   
Issuer, description    rate (%)  date  rating (A)  ($000)  Value 
Short-term investments 0.36%          $4,000,000 
(Cost $4,000,000)             
 

Government U.S. Agency 0.36%
 
          4,000,000 

Federal Home Loan Bank, Disc Note    3.150  09-01-05  AAA  4,000  4,000,000 
 
Total investments 100.00%          $1,106,220,446 

Page 6


John Hancock       
Preferred Income Fund III     
Financial futures contracts     
August 31, 2005 (unaudited)     
 
  Number of     
Open contracts  contracts  Position Expiration  Depreciation 

U.S. 10-Year Treasury Note  1,100  Short Dec-05  ($1,565,179) 

Financial futures contracts


John Hancock         
Preferred Income Fund III       
Interest rate swap contracts       
August 31, 2005 (unaudited)       
 
  Rate type       

Notional  Payments made  Payments received  Termination   
amount  by Fund  by Fund  date  Appreciation 

$35,000,000  4.00% (a)  3-month LIBOR  Apr 09  $289,512 

 
(a) Fixed rate         

Interest rate swap contracts


John Hancock

Preferred Income Fund III

Footnotes to Schedule of Investments

August 31, 2005 (unaudited)

(A)      Credit ratings are unaudited and are rated by Moody's Investors Service where Standard & Poor's ratings are not available.
 
(S)      This security is exempt from registration under Rule 144A of the Securities Act of 1933. Such security may be resold, normally to qualified institutional buyers, in transactions exempt from registration. Rule 144A securities amounted to $16,830,937 or 1.52% of the Fund's total investments as of August 31, 2005. 
 
  Parenthetical disclosure of a foreign country in the security description represents country of a foreign issuer.
 
  The percentage shown for each investment category is the total value of that category as a percentage of the total investments of the Fund.
 
  The cost of investments owned on August 31, 2005, including short-term investments, was $1,081,874,880. Gross unrealized appreciation and depreciation of investments aggregated $41,460,487 and $17,114,921, respectively, resulting in net unrealized appreciation of $24,345,566.
 

Footnotes to Schedule of Investments - Page 1




ITEM 2. CONTROLS AND PROCEDURES.

(a) Based upon their evaluation of the registrant's disclosure controls and procedures as conducted within 90 days of the filing date of this Form N-Q, the registrant's principal executive officer and principal accounting officer have concluded that those disclosure controls and procedures provide reasonable assurance that the material information required to be disclosed by the registrant on this report is recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission's rules and forms.

(b) There were no changes in the registrant's internal control over financial reporting that occurred during the registrant's last fiscal quarter that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting.

ITEM 3. EXHIBITS.

Separate certifications for the registrant's principal executive officer and principal accounting officer, as required by Rule 30a-2(a) under the Investment Company Act of 1940, are attached.


SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

John Hancock Preferred Income Fund III
By: /s/ Keith F. Hartstein
-------------------------------------
Keith F. Hartstein
President and Chief Executive Officer
Date: October 27, 2005

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By: /s/ Keith F. Hartstein
-------------------------------------
Keith F. Hartstein
President and Chief Executive Officer
Date: October 27, 2005

By: /s/ John G. Vrysen
-------------------------------------
John G. Vrysen

Executive Vice President and Chief Financial Officer

Date: October 27, 2005