Affirmative action is a controversial policy. Lauded by many, the attempt at social engineering has also been condemned by some as unnecessary and by others as counterproductive to the goal of social equality. As such, affirmative action is ideally situated to benefit from psychological research pertaining to the need for and the effectiveness of the policy. This article discusses both the potential benefits to American society of affirmative action and the potential costs of such a policy. Concluding that affirmative action is useful, we end with a look at ways to make affirmative action programs as effective as possible.