This article argues that regional economic development policies should aim to correct failures of private markets to achieve efficiency. Market failures that may rationalize regional economic development policies include involuntary unemployment, involuntary underemployment, fiscal benefits, agglomeration economies, research spillovers, imperfect human capital markets, imperfect information markets, and imperfect financial markets. Development policies to correct market failures may be evaluated by the nonmarket benefits created for society. The market failure approach focuses policymakers' attention on areas where private market performance is weakest and allows comparisons of development policies.