CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in this Post-Effective Amendment
No. 1 to Registration Statement No. 333-140895 of First Trust Exchange-Traded
AlphaDEX(TM) Fund (comprising, First Trust Consumer Discretionary AlphaDEX(TM)
Fund, First Trust Consumer Staples AlphaDEX(TM) Fund, First Trust Energy
AlphaDEX(TM) Fund, First Trust Financials AlphaDEX(TM) Fund, First Trust Health
Care AlphaDEX(TM) Fund, First Trust Industrials/Producer Durables AlphaDEX(TM)
Fund, First Trust Materials AlphaDEX(TM) Fund, First Trust Technology
AlphaDEX(TM) Fund, First Trust Utilities AlphaDEX(TM) Fund, First Trust Large
Cap Core AlphaDEX(TM) Fund, First Trust Mid Cap Core AlphaDEX(TM) Fund, First
Trust Small Cap Core AlphaDEX(TM) Fund, First Trust Large Cap Value
Opportunities AlphaDEX(TM) Fund, First Trust Large Cap Growth Opportunities
AlphaDEX(TM) Fund, First Trust Multi Cap Value AlphaDEX(TM) Fund, and First
Trust Multi Cap Growth AlphaDEX(TM) Fund) on Form N-1A of our report dated
September 14, 2007, appearing in the Annual Report for the year ended July 31,
2007, and to the references to us under the headings "Financial Highlights" in
the Prospectus and "Financial Statements" and "Independent Registered Public
Accounting Firm" in the Statement of Additional Information, which are a part of
such Registration Statement.

DELOITTE & TOUCHE LLP
Chicago, IL

November 15, 2007