EXHIBIT 4.1 Advisors Asset Management, Inc. 18925 Base Camp Road Monument, Colorado 80132 July 16, 2008 Advisors Disciplined Trust 256 c/o The Bank of New York Mellon, as Trustee BNY Atlantic Terminal 2 Hanson Place, 12th Floor Brooklyn, New York 11217 Re: Advisors Disciplined Trust 256 Value Line Select ETF Index Portfolio, Series 1 ----------------------------------------------- Ladies and Gentlemen: We have examined the Registration Statement File No. 333-151423 for the above captioned fund. We hereby consent to the use in the Registration Statement of the references to Advisors Asset Management, Inc. as evaluator. You are hereby authorized to file a copy of this letter with the Securities and Exchange Commission. Sincerely, ADVISORS ASSET MANAGEMENT, INC. By /s/ ALEX R. MEITZNER ------------------------------ Senior Vice President