This Amendment Number 4 to Schedule 13G (this “Amendment”) is filed by Madison Dearborn Capital Partners II, L.P., Madison Dearborn Partners II, L.P. and Madison Dearborn Partners, Inc. (collectively, the “Reporting Persons”). This Amendment hereby amends and supplements the initial Schedule 13G filed by Madison Dearborn Capital Partners II, L.P. on February 14, 2001, as amended (the “Initial Schedule 13G”). Capitalized terms used herein but not defined shall have the meaning ascribed thereto in the Initial Schedule 13G.

Item 1(a) Name of Issuer:

Item 1(b) Address of Issuer’s Principal Executive Offices:

Item 2(a), Item 2(b) and Item 2(c)
Name of Person Filing, Address of Principal Business Office and Citizenship:

     Pursuant to Rule 13d-1(k)(1)-(2) of Regulation 13D-G of the General Rules and Regulations under the Securities Exchange Act of 1934 (the “Exchange Act”), this Amendment is filed on behalf of the Reporting Persons who, pursuant to Rule 13d-5(b)(1), along with certain individuals and corporations (the “Non-Reporting Persons”) may be deemed as a group to have beneficial ownership of the Class A Common Stock (the “Class A Common Stock”) of Nextel Partners, Inc. as a result of a Reporting Persons and the Non-Reporting Persons being signatories to a Shareholders Agreement. The Reporting Persons beneficially own 6.8% of the outstanding Class A Common Stock of Nextel Partners, Inc. Neither the fact of this filing nor anything contained herein shall be deemed to be an admission by the Reporting Persons that a group exists within the meaning of the Exchange Act.

     Reporting Persons:

Item 4 Ownership:

           Although the Reporting Persons and each Non-Reporting Person disclaim beneficial ownership of any shares of Class A Common Stock beneficially owned by each other Non-Reporting Person, pursuant to the Exchange Act and the regulations thereunder, the Reporting Persons and the Non-Reporting Persons may be deemed as a group to have beneficial ownership of 26,248,181 shares of Class A Common Stock, the aggregate number of shares of Common Stock which are beneficially subject to the terms of the Shareholders Agreement, representing 14.4% of the outstanding Class A Common Stock as of December 31, 2004.

           The Reporting Persons have sole power to vote and dispose of 12,349,179 shares, or 6.8% of the outstanding shares, of Class A Common Stock.

The Reporting Persons disclaim beneficial ownership of all shares of which they may be deemed to have shared power to vote or dispose. The ownership information set forth above pertaining to shared dispositive and voting power in respect of the Class A Common Stock is based solely on (i) the record ownership by the Reporting Persons, (ii) information provided in public filings and (iii) information provided to the Reporting Persons by the Non-Reporting Persons pursuant to the provisions of the Shareholders Agreement. To the extent information provided in this Item is derived from information described in clause (ii) or (iii) of the immediately preceding sentence, it is subject in its entirety to the accuracy of such information.

Item 5 Certification:

          By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

SIGNATURE

          After reasonable inquiry and to the best of our knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: February 15, 2005