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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
 WASHINGTON, D.C. 20549
 FORM 11-K
 þ
    
    ANNUAL REPORT PURSUANT TO SECTION 15(d)
OF THE SECURITIES EXCHANGE ACT OF 1934
 FOR THE FISCAL YEAR ENDED DECEMBER 31, 2006
 OR
 o
    
    TRANSITION REPORT PURSUANT TO SECTION 15(d)
OF THE SECURITIES EXCHANGE ACT OF 1934
 FOR THE TRANSITION PERIOD FROM  TO
 COMMISSION FILE NUMBER 001-15423
 GRANT PRIDECO, INC. 401(k) SAVINGS PLAN
 Grant Prideco, Inc.




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GRANT PRIDECO, INC.
401(k) SAVINGS PLAN
 FINANCIAL STATEMENTS
and SUPPLEMENTAL SCHEDULE
 DECEMBER 31, 2006 and 2005




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Table of Contents
 Report of Independent Registered Public Accounting Firm
    
    
    1Audited Financial StatementsStatements of Net Assets Available for Benefits
    
    
    2Statement of Changes in Net Assets Available for Benefits
    
    
    3Notes to Financial Statements
    
    
    4Supplemental ScheduleSchedule H, Line 4i  Schedule of Assets (Held At End of Year)
    
    
    10Signature
    
    
    11Exhibits
    
    
    12
 Schedules not filed herein are omitted because of the absence of conditions under which they are
required.




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REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM




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December 31,2006
    
    2005AssetsCash
    
    $
    31,856
    
    
    $
    70,241Investments, at fair value
    
    
    77,256,511
    
    
    
    64,560,391Investment income receivable
    
    
    3,996
    
    
    
    1,273Total assets
    
    
    77,292,363
    
    
    
    64,631,905LiabilitiesTotal liabilities
    
    
    
    
    
    
    Net assets available for benefits at fair value
    
    
    77,292,363
    
    
    
    64,631,905Adjustment from fair value to contract value
for
investments in fully benefit-responsive
contracts
    
    
    132,649
    
    
    
    206,287Net assets available for benefits
    
    $
    77,425,012
    
    
    $
    64,838,192
 See accompanying notes.
 2




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Additions -Net appreciation in fair value of investments
    
    $
    3,629,529Investment income
    
    
    2,528,806Participant contributions
    
    
    7,624,873Employer contributions
    
    
    3,772,837Rollovers
    
    
    1,004,472Total additions
    
    
    18,560,517Deductions -Benefits paid to participants and beneficiaries
    
    
    5,948,798Administrative expenses
    
    
    24,899Total deductions
    
    
    5,973,697Net increase
    
    
    12,586,820Net assets available for benefits, beginning of the year
    
    
    64,838,192Net assets available for benefits, end of the year
    
    $
    77,425,012
 See accompanying notes.
 3




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1. Description of the Plan
  General
  Contributions
    4




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1. Description of the Plan (continued)
 Participant Accounts
  Participant Loans
  Vesting
  Withdrawals and Terminations
 1 2
  5




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1. Description of the Plan (continued)
 Expenses of the Plan
  Plan Termination
  2. Summary of Significant Accounting Policies
 Basis
of Accounting and Use of Estimates
   6




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2. Summary of Significant Accounting Policies (continued)
 Investment Valuation and Income Recognition
    Determination of Realized and Unrealized Gain or Loss on Investments
  New Accounting Pronouncements
 Reporting of Fully Benefit-Responsive Investment
Contracts Held by Certain Investment Companies Subject to the AICPA Investment Company Guide and
Defined-Contribution Health and Welfare and Pension Plans
 Fair Value Measurements
 7




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3. Investments
  December 31,2006
    
    2005Merrill Lynch Equity Index Trust (Class I)
    
    $
    
    
    
    $
    6,802,336Merrill
Lynch Retirement Preservation Trust*
    
    
    6,984,079
    
    
    
    11,541,763Phoenix-Engmann Small-Cap Growth Fund (Class A)
    
    
    
    
    
    
    6,262,108BlackRock International Value Fund (Class I)
    
    
    8,279,820
    
    
    
    3,963,004BlackRock Balanced Capital Fund (Class I)
    
    
    
    
    
    
    7,472,463BlackRock Bond Fund (Class I)
    
    
    **
    
    
    
    6,051,504Davis New York Venture Fund (Class A)
    
    
    11,309,785
    
    
    
    6,855,444Common Stock of Grant Prideco, Inc.
    
    
    8,899,996
    
    
    
    8,782,598Loomis Sayles Strategic Income Fund (Class A)
    
    
    16,549,809
    
    
    
    Loomis Sayles Growth Fund (Class A)
    
    
    8,863,456
    
    
    
    
 
 *
    
    Contract value for the Merrill Lynch Retirement Preservation
Trust is $7,116,728 for 2006 and $11,748,050 for 2005, respectively.**
    
    Amount less than 5% of net assets available for benefits.  2006Common/collective trusts
    
    $
    402,631Mutual funds
    
    
    3,778,063Common stocks
    
    
    (551,165
    )$
    3,629,529
 4. Risks and Uncertainties
  8




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5. Tax Status
  6. Related Party Transactions
  7. Reconciliation of Financial Statements to Form 5500
  2006
    
    
    2005Net assets available for benefits per the financial
statements
    
    $
    77,425,012
    
    
    $
    64,838,192Adjustment from contract value to fair value for fully
benefit-responsive investment contracts
    
    
    (132,649
    )
    
    
    Net assets available for benefits per Form 5500
    
    $
    77,292,363
    
    
    $
    64,838,192
  2006Net increase in net assets
available for benefits per the financial statements
    
    $
    12,586,820Adjustment from contract value to fair value for fully
benefit-responsive investment contracts
    
    
    (132,649
    )Net
increase in net assets
available for benefits per Form 5500
    
    $
    12,454,171
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Supplemental Schedule




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Grant Prideco, Inc. 401(k) Savings Plan
 Schedule H, Line 4i  Schedule of Assets (Held At End of Year)
  December 31, 2006
 Current(a)(b)Identity of Issue
    

(c)Description of Investment
    

(e)Value*Merrill Lynch
    
    Merrill Lynch Retirement Preservation Trust
    
    $
    6,984,079*BlackRock, Inc.
    
    BlackRock International Value Fund (Class I)
    
    
    8,279,820*BlackRock, Inc.
    
    BlackRock Bond Fund (Class I)
    
    
    150,893Davis Venture Group
    
    Davis New York Venture Fund (Class A)
    
    
    11,309,785*Grant Prideco, Inc.
    
    Common Stock of Grant Prideco, Inc.
    
    
    8,899,996Loomis Sayles & Co.
    
    Loomis Sayles Strategic Income Fund
(Class A)
    
    
    16,549,809Loomis Sayles & Co.
    
    Loomis Sayles Growth Fund (Class A)
    
    
    8,863,456Weatherford
International, Ltd
    
    Common Stock of Weatherford International, Ltd.
    
    
    387,195Columbia Funds
    
    Columbia Acorn Select Fund (Class A)
    
    
    2,764,474Fidelity Advisor
    
    Fidelity Advisor Leveraged Company Stock Fund (Class T)
    
    
    3,410,285Oppenheimer Funds
    
    Oppenheimer International Small Cap (Class A)
    
    
    2,138,706Fidelity Advisor
    
    Fidelity Advisor Small Cap Fund (Class T)
    
    
    1,680,769Oppenheimer Funds
    
    Oppenheimer Small & Mid Cap Value Fund (Class A)
    
    
    2,755,176*Participant loans
    
    Various maturity dates, interest rates at 5.0%  10.5%
    
    
    3,082,068$
    77,256,511
 
 *
    
    Party-in-interest  10




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SIGNATURE
  GRANT PRIDECO, INC. 401(k) SAVINGS PLANDate:  June 29, 2007
    /s/ Mr. Lias J. SteenMr. Lias J. SteenVice President, Human Resources,
For Grant Prideco, Inc., and
Administrative Committee Member 11




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INDEX TO EXHIBITS
 ExhibitNumber23.1
    
    Consent of Independent Registered Public Accounting Firm  Pannell Kerr Forster of Texas, P.C.
 12