It was hypothesized that the degree of intention formation moderates the way in which attitudes influence behavior. Degree of intention formation-how well-formed intentions are-was manipulated by facilitating or disrupting the process of intention formation in a field experiment. As predicted, the degree to which intentions were well formed affected the way in which attitudes influenced behavior. When intentions were well formed, they completely mediated the effects of attitudes on behavior, in keeping with the theory of reasoned action. When intentions were poorly formed, however, the mediating role of intentions was reduced, and attitudes had a direct effect on behavior. The theoretical and practical implications of these findings for understanding the attitude-behavior relationship are discussed.