CHAPMAN AND CUTLER LLP 111 WEST MONROE STREET CHICAGO, ILLINOIS 60603 May 9, 2011 VIA EDGAR CORRESPONDENCE Houghton Hallock United States Securities and Exchange Commission 100 F Street, N.E. Washington, D.C. 20549 Re: First Trust Exchange-Traded AlphaDEX(R) Fund (File Nos. 333-140895, 811-22019) --------------------------------------------- Dear Mr. Hallock: This letter responds to your comments regarding the registration statement filed on Form N-1A for First Trust Exchange-Traded AlphaDEX(R) Fund (the "Trust") with the Securities and Exchange Commission (the "Commission") on March 25, 2011. The First Trust Mega Cap AlphaDEX(R) Fund, (the "Fund") is a series of the Trust. Your comments were transmitted to us via telephone conference on May 9, 2011. This letter serves to respond to your comments. Please also note that to the extent that your previous comments to recently filed registration statements for the First Trust family of exchange-traded funds applied, we have made the corresponding changes to the prospectus and statement of additional information of this Fund. COMMENT 1 Please provide an undertaking that the Fund will not be paying any 12b-1 fees without providing prior notice to the Commission. RESPONSE TO COMMENT 1 The Trust, on behalf of the Fund, has committed to provide the staff of the Commission with notice prior to initiating the payment by the Fund of any Rule 12b-1 fees. COMMENT 2 Please revise the first sentence on the cover of the prospectus to include the words "is an exchange-traded index fund organized as a separate series" replacing "is a series" and the remainder of the sentence after "company." In the second paragraph on the cover, delete "issued and redeemed." RESPONSE TO COMMENT 2 The cover has been revised in accordance with this comment. COMMENT 3 On page 1 of the prospectus, under "Example," replace "in the secondary market" with "on NYSE Arca." RESPONSE TO COMMENT 3 The prospectus has been revised in accordance with this comment. COMMENT 4 On page 1 of the prospectus, under "Principal Investment Strategies" and under "Investment Strategies," add "plus the amount of any borrowings for investment purposes" after "net assets." RESPONSE TO COMMENT 4 The prospectus has been revised in accordance with this comment. COMMENT 5 On page 1 of the prospectus, under "Principal Investment Strategies," please provide the capitalization range of the Index. Also, please move the sentence under "Market Capitalization Risk" that starts with "The securities of the companies represented in the Index," to the "Principal Investment Strategies" section. RESPONSE TO COMMENT 5 The prospectus has been revised in accordance with this comment. COMMENT 6 Under "Index Information," please provide additional information regarding the S&P BMI US Index. RESPONSE TO COMMENT 6 The prospectus has been revised in response to this comment. COMMENT 7 In the fee table, please insert a footnote stating that the Fund has adopted a 12b-1 plan that permits it to pay up to 0.25% per annum, it will not pay 12b-1 fees at any time before May 6, 2012. RESPONSE TO COMMENT 7 The prospectus has been revised in response to this comment. *** TANDY ACKNOWLEDGMENT In connection with the Trust's registration statement, the Trust acknowledges that; o should the Commission or the staff, acting pursuant to delegated authority, declare the filing effective, it does not foreclose the Commission from taking any action with respect to the filing; o the action of the Commission or the staff, acting pursuant to delegated authority in declaring the filing effective, does not relieve the Trust from its full responsibility for the adequacy and accuracy for the disclosure in the filing; and o the Trust may not assert this action as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States. Please call me at (312) 845-3484 if you have any questions or issues you would like to discuss regarding these matters. Sincerely yours, CHAPMAN AND CUTLER LLP By: /s/ Morrison C. Warren ----------------------------- Morrison C. Warren