MANAGEMENT MEMBERS AGREEMENT

Exhibit 10.63

MANAGEMENT MEMBERS AGREEMENT

CONCERNING

NALCO LLC

DATED AS OF JUNE 11, 2004.

1

This MANAGEMENT MEMBERS AGREEMENT (the ‘‘Agreement’’) dated as of June 11, 2004 by and among Nalco LLC (the ‘‘Company’’), a Delaware limited liability company and the Persons who are or after the date hereof become signatories hereto (the ‘‘Management Members’’).

RECITALS

WHEREAS, the Company is governed by that certain Second Amended and Restated Limited Liability Company Operating Agreement (the ‘‘LLC Agreement’’) dated as of May 17, 2004.

WHEREAS, the Management Members will be providing services to the Company or its Affiliates.

WHEREAS, each Management Member will subscribe for and acquire from the Company, and the Company will issue and sell to each Management Member, the Company’s Class A Units (the ‘‘Units’’), in the amounts set forth on Schedule A to the LLC Agreement, as the same may be amended from time to time;

WHEREAS, it is a condition to the sale of the Units that the Management Members enter into this Agreement;

WHEREAS, the Management Members will enter into the Registration Rights Agreement; and

NOW, THEREFORE, in consideration of the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties to this Agreement hereby agree as follows:

ARTICLE I

Management Members’ Representations, Warranties and Agreements

Section 1.01.    Units Unregistered.    Each Management Member acknowledges and represents that such Management Member has been advised by the Company that: