| Delaware                             | 20-5639997                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|--------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| (State      or Other Jurisdiction of | (I.R.S.      Employer Identification No.)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| Incorporation      or Organization)  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|                                 | 1100      Louisiana, 10th Floor, Houston, Texas                          77002                                                                                                                                                                                                                                                                                                                                                              |   |
|                                 |     (Address      of Principal Executive      Offices)                                                                              (Zip      Code) |   |
|                                 | (713)      381-6500                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |   |
|                                 | (Registrant's      Telephone Number, Including Area Code)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |   |

| Title of Each      Class |   |  Name of Each Exchange      On Which Registered                                                                         |   |
|--------------------------|--------|------------------------------------------------------------------------------------------------------------------------------|--------|
| Common      Units        |   |                 New      York Stock Exchange |   |

| Large      accelerated filer o                                                                               |   |  Accelerated      filer þ                                                                                              |
|--------------------------------------------------------------------------------------------------------------|--------|----------------------------------------------------------------------------------------------------------------------------------|
| Non-accelerated      filer   o      (Do not check if a smaller reporting company)   |   |                 Smaller      reporting company o |

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EXPLANATORY NOTE

| (a)   | The      following documents are filed as a part of this  Report: |
|-----------------|-------------------------------------------------------------------|

| (1)   | Financial      Statements:  See Index to Consolidated Financial Statements on      page F-1 of this Report for financial statements filed as part of this      Report. |
|-----------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| (2)   | Financial      Statement Schedules:  All schedules have been omitted because      they are either not applicable, not required or the information called for      therein appears in the consolidated financial statements or notes      thereto. |
|-----------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| (3)   | Exhibits. |
|-----------------|-----------|

| Exhibit      Number | Exhibit*                                                                                                                                                                                                                                                                             |
|---------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 3.1                 | Certificate      of Limited Partnership of Duncan Energy Partners L.P. (incorporated by      reference to Exhibit 3.1 to Form S-1 Registration Statement (Reg. No.      333-138371) filed November 2, 2006).                                                                         |
| 3.2                 | Amended      and Restated Agreement of Limited Partnership of Duncan Energy Partners      L.P., dated February 5, 2007 (incorporated by reference to Exhibit      3.1 to Form 8-K filed February 5, 2007).                                                                      |
| 3.3                 | First      Amendment to Amended and Restated Partnership Agreement of Duncan Energy      Partners L.P. dated as of December 27, 2007 (incorporated by      reference to Exhibit 3.1 to Form 8-K/A filed January 3,    2008).                                                    |
| 3.4                 | Second      Amendment to Amended and Restated Partnership Agreement of Duncan Energy      Partners L.P. dated as of November 6, 2008 (incorporated by reference to      Exhibit 3.4 to Form 10-Q for the period ended September 30, 2008, filed on      November 10, 2008).          |
| 3.5                 | Third      Amendment to Amended and Restated Partnership Agreement of Duncan Energy      Partners L.P., dated December 8, 2008 (incorporated by reference to      Exhibit 3.1 to Form 8-K filed December 8, 2008).                                                                   |
| 3.6                 | Second      Amended and Restated Limited Liability Company Agreement of DEP Holdings,      LLC, dated May 3, 2007 (incorporated by reference to Exhibit 3.4 to Form      10-Q for the period ended March 31, 2007, filed on May 4,      2007).                                       |
| 3.7                 | First      Amendment to the Second Amended and Restated Limited Liability Company      Agreement of DEP Holdings, LLC, dated November 6, 2008 (incorporated by      reference to Exhibit 3.8 to Form 10-Q for the period ended September 30,      2008, filed on November 10, 2008). |
| 3.8                 | Certificate      of Formation of DEP OLPGP, LLC (incorporated by reference to Exhibit 3.5      to Form S-1 Registration Statement (Reg. No. 333-138371) filed November 2,      2006).                                                                                                |

----

| 3.9     | Amended      and Restated Limited Liability Company Agreement of DEP OLPGP, LLC, dated      January 19, 2007 (incorporated by reference to Exhibit 3.6 to Amendment      No. 3 to Form S-1 Registration Statement (Reg. No. 333-138371) filed      January 22, 2007).                                                                                                                                                                                                                                                                                                                                                                                                               |
|---------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 3.10    | Certificate      of Limited Partnership of DEP Operating Partnership, L.P. (incorporated by      reference to Exhibit 3.7 to Form S-1 Registration Statement (Reg. No.      333-138371) filed November 2, 2006).                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| 3.11    | Agreement      of Limited Partnership of DEP Operating Partnership, L.P., dated September      29, 2006 (incorporated by reference to Exhibit 3.8 to Amendment No. 1 to      Form S-1 Registration Statement (Reg. No. 333-138371) filed December 15,      2006).                                                                                                                                                                                                                                                                                                                                                                                                                   |
| 4.1     | Revolving      Credit Agreement, dated as of January 5, 2007, among Duncan Energy      Partners L.P., as borrower, Wachovia Bank, National Association, as      Administrative Agent, The Bank of Nova Scotia and Citibank, N.A., as      Co-Syndication Agents, JPMorgan Chase Bank, N.A. and Mizuho Corporate      Bank, Ltd., as Co-Documentation Agents, and Wachovia Capital Markets, LLC,      The Bank of Nova Scotia and Citigroup Global Markets Inc., as Joint Lead      Arrangers and Joint Book Runners (incorporated by reference to Exhibit      10.20 to Amendment No. 2 to Form S-1 Registration Statement (Reg. No.      333-138371) filed January 12, 2007). |
| 4.2     | First      Amendment to Revolving Credit Agreement, dated as of June 30, 2007, among      Duncan Energy Partners L.P., as borrower, Wachovia Bank, National      Association, as Administrative Agent, The Bank of Nova Scotia and      Citibank, N.A., as Co-Syndication Agents, JPMorgan Chase Bank, N.A. and      Mizuho Corporate Bank, Ltd., as Co-Documentation Agents, and Wachovia      Capital Markets, LLC, The Bank of Nova Scotia and Citigroup Global Markets      Inc., as Joint Lead Arrangers and Joint Book Runners (incorporated by      reference to Exhibit 4.2 to the Form 10-Q filed on August 8,      2007).                                                 |
| 4.3     | Term      Loan Agreement, dated as of April 18, 2008, among Duncan Energy Partners      L.P., the lenders party thereto, Wachovia Bank, National Association, as      Administrative Agent, Suntrust Bank and The Bank of Nova Scotia, as      Co-Syndication Agents, and Mizuho Corporate Bank, Ltd. and The Royal Bank      of Scotland plc, as Co-Documentation Agents (incorporated by reference to      Exhibit 10.7 of Form 8-K filed December 8, 2008).                                                                                                                                                                                                                      |
| 4.4     | First      Amendment to Term Loan Agreement, dated as of July 11, 2008, among Duncan      Energy Partners L.P., Wachovia Bank, National Association, as      Administrative Agent, and the Lenders party thereto (incorporated by      reference to Exhibit 10.8 of Form 8-K filed December 8,    2008).                                                                                                                                                                                                                                                                                                                                                                            |
| 10.1*** | Amended      and Restated Enterprise Products 2008 Long-Term Incentive Plan      (incorporated by reference to Exhibit 4.1 to the Form S-8 filed      by Enterprise Products Partners L.P. on May 6, 2008).                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| 10.2*** | Form      of Option Grant Award under Enterprise Products 2008 Long-Term Incentive      Plan (incorporated by reference to Exhibit 4.3 to the Form S-8      filed by Enterprise Products Partners L.P. on May 6,  2008).                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| 10.3*** | Form      of Restricted Unit Grant Award under Enterprise Products 2008 Long-Term      Incentive Plan (incorporated by reference to Exhibit 4.2 to the      Form S-8 filed by Enterprise Products Partners L.P. on May 6,      2008).                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| 10.4*** | Form      of Option Grant Award under Enterprise Products 1998 Long-Term Incentive      Plan for awards issued after May 7, 2008 (incorporated by reference to      Exhibit 10.4 to the Form 10-Q filed by Enterprise Products      Partners L.P. on May 12, 2008).                                                                                                                                                                                                                                                                                                                                                                                                       |
| 10.5*** | Amendment      to Form of Option Grant Award under Enterprise Products 1998 Long-Term      Incentive Plan for awards issued after April 10, 2007 but before May 7,      2008 (incorporated by reference to Exhibit 10.5 to the Form 10-Q      filed by Enterprise Products Partners L.P. on May 12,    2008).                                                                                                                                                                                                                                                                                                                                                             |
| 10.6*** | Enterprise      Unit L.P. Agreement of Limited Partnership dated February 20, 2008      (incorporated by reference to Exhibit 10.1 to the Form 8-K filed      by Enterprise Products Partners L.P. on February 26,  2008).                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| 10.7*** | Second      Amendment to Agreement of Limited Partnership of EPE Unit L.P. dated July      1, 2008 (incorporated by reference to Exhibit 10.1 to Form 8-K filed by      Enterprise GP Holdings L.P. on July 7, 2008).                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| 10.8*** | Second      Amendment to Agreement of Limited Partnership of EPE Unit II, L.P. dated      July 1, 2008 (incorporated by reference to Exhibit 10.2 to Form 8-K filed      by Enterprise GP Holdings L.P. on July 7,2008).                                                                                                                                                                                                                                                                                                                                                                                                                                                            |

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| 10.9*** | Second      Amendment to Agreement of Limited Partnership of EPE Unit III, L.P. dated      July 1, 2008 (incorporated by reference to Exhibit 10.3 to Form 8-K filed      by Enterprise GP Holdings L.P. on July 7, 2008).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|---------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 10.10   | Second      Amended and Restated Limited Liability Company Agreement of Mont Belvieu      Caverns, LLC, dated November 6, 2008 (incorporated by reference to Exhibit      10.4 to Form 10-Q for the period ended September 30, 2008, filed on      November 10, 2008)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| 10.11   | Purchase      and Sale Agreement dated as of December 8, 2008 by and among (a)      Enterprise Products Operating LLC and Enterprise GTM Holdings L.P. as the      Seller Parties and (b) Duncan Energy Partners L.P., DEP Holdings, LLC, DEP      Operating Partnership, L.P. and DEP OLP GP, LLC as the Buyer Parties      (incorporated by reference to Exhibit 10.1 of Form 8-K filed December 8,      2008).                                                                                                                                                                                                                                                                                                                                                             |
| 10.12   | Contribution,      Conveyance and Assumption Agreement dated as of December 8, 2008 by and      among Duncan Energy Partners L.P., DEP OLPGP, LLC, DEP Operating      Partnership, L.P., Enterprise GTM Holdings L.P. and Enterprise Holding      III, L.L.C. (incorporated by reference to Exhibit 10.2 of Form 8-K filed      December 8, 2008).                                                                                                                                                                                                                                                                                                                                                                                                                            |
| 10.13   | Third      Amended and Restated Agreement of Limited Partnership of Enterprise GC,      L.P. dated as of December 8, 2008 (incorporated by reference to Exhibit      10.3 of Form 8-K filed December 8, 2008).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| 10.14   | Fourth      Amended and Restated Agreement of Limited Partnership of Enterprise      Intrastate L.P. dated as of December 8, 2008 (incorporated by reference to      Exhibit 10.4 of Form 8-K filed December 8, 2008).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| 10.15   | Amended      and Restated Company Agreement of Enterprise Texas Pipeline LLC dated      as of December 8, 2008 (incorporated by reference to Exhibit 10.5 of Form      8-K filed December 8, 2008).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| 10.16   | Amended      and Restated Omnibus Agreement dated as of December 8, 2008 among      Enterprise Products Operating LLC, DEP Holdings, LLC, Duncan Energy      Partners L.P., DEP OLPGP, LLC, DEP Operating Partnership, L.P., Enterprise      Lou-Tex Propylene Pipeline L.P., Sabine Propylene Pipeline L.P., Acadian      Gas, LLC, Mont Belvieu Caverns, LLC, South Texas NGL Pipelines, LLC,      Enterprise Holding III, L.L.C., Enterprise Texas Pipeline LLC, Enterprise      Intrastate L.P. and Enterprise GC, LP (incorporated by reference to      Exhibit 10.6 of Form 8-K filed December 8, 2008).                                                                                                                                                                |
| 10.17   | Unit      Purchase Agreement, dated as of December 8, 2008, by and between Duncan      Energy Partners L.P. and Enterprise Products Operating LLC (incorporated      by reference to Exhibit 10.9 of Form 8-K filed December 8,      2008).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| 10.18   | Fifth      Amended and Restated Administrative Services Agreement by and among EPCO,      Inc., Enterprise Products Partners L.P., Enterprise Products Operating      L.P., Enterprise Products GP, LLC, Enterprise Products OLPGP, Inc.,      Enterprise GP Holdings L.P., EPE Holdings, LLC, DEP Holdings, LLC, Duncan      Energy Partners L.P., DEP OLPGP, LLC, DEP Operating Partnership L.P.,      TEPPCO Partners, L.P., Texas Eastern Products Pipeline Company, LLC, TE      Products Pipeline Company, Limited Partnership, TEPPCO Midstream      Companies, L.P., TCTM, L.P. and TEPPCO GP, Inc. dated January 30, 2009      (incorporated by reference to Exhibit 10.1 to the Form 8-K filed by      Enterprise Products Partners L.P. on February 5, 2009). |
| 12.1#   | Computation      of ratio of earnings to fixed charges for each of the five years ended      December 31, 2008, 2007, 2006, 2005 and 2004.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| 21.1#   | List      of Subsidiaries of Duncan Energy Partners L.P.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| 31.1+   | Sarbanes-Oxley      Section 302 certification of Richard H. Bachmann for Duncan Energy      Partners L.P. for the December 31, 2008 annual report on Form      10-K/A.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| 31.2+   | Sarbanes-Oxley      Section 302 certification of W. Randall Fowler for Duncan Energy Partners      L.P. for the December 31, 2008 annual report on Form    10-K/A.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| 32.1#   | Section      1350 certification of Richard H. Bachmann for the December 31, 2008 annual      report on Form 10-K.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| 32.2#   | Section      1350 certification of W. Randall Fowler for the December 31, 2008 annual      report on Form 10-K.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |

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| * | With      respect to exhibits incorporated by reference to Exchange Act filings, the      Commission file number for Enterprise Products Partners L.P. is 1-14323;      Enterprise GP Holdings L.P., 1-32610; and Duncan Energy Partners L.P.,      1-33266. |
|---|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| *** | Identifies      management contract and compensatory plan  arrangements. |
|-----|--------------------------------------------------------------------------|

| # | Filed      with the Annual Report on Form 10-K for the year ended December 31, 2008      filed with the Securities and Exchange Commission on March 2,      2009. |
|---|-------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| + | Filed      herewith. |
|---|----------------------|

|   |   |   |   |   | DUNCAN      ENERGY PARTNERS L.P.                                                                                                                                                                                                                                                                                                                                              |
|--------|--------|--------|--------|--------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   |   |   |   |   | (A      Delaware Limited Partnership)                                                                                                                                                                                                                                                                                                                                         |
|   |   |   |   |   |                                                                                                                                                                                                                                                                                                                                                                          |
|   |   |   |   |   | By:    DEP      Holdings, LLC, as General Partner                                                                                                                                                                                                                                                                                                         |
|   |   |   |   |   |                                                                                                                                                                                                                                                                                                                                                                          |
|   |   |   |   |   | By:             /s/ Michael J.      Knesek                                            |
|   |   |   |   |   | Name:  Michael      J. Knesek                                                                                                                                                                                                                                                                                                                                       |
|   |   |   |   |   | Title:    Senior      Vice President, Controller             and      Principal Accounting Officer             of      the General Partner                                                                              |

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