Background: This study evaluated a decisional balance intervention among heavy drinking undergraduates and compared a nonweighted decisional balance proportion (DBP; Collins, Carey, & Otto, 2009) to a participant-weighted DBP with weights based on relative importance of items. We expected: (1) the intervention to decrease drinking compared to control; (2) the weighted intervention to be more effective compared to the nonweighted or control in reducing drinking; and (3) intervention efficacy to be moderated by initial DBP. Method: Participants (N = 162, Mean age = 24.37, SD = 6.81, 27% male) were randomly assigned to an alcohol intervention wherein they were either asked to assign weights of importance to pros and cons (weighted intervention), or not (nonweighted intervention), or to control. Participants completed web-based questionnaires at baseline and again during a one month follow-up assessment. Results: Consistent with expectations, the nonweighted intervention was associated with reduced follow-up weekly drinking, and the weighted intervention was associated with reductions in drinking frequency. Results further indicated that initial decisional balance did not moderate intervention efficacy. Discussion: Findings suggest that the decisional balance procedure can reduce drinking but there was not compelling evidence for the addition of weights. This study lays the groundwork for enhancing future interventions by increasing empirical knowledge of the role motivation plays in heavy alcohol use.