Results of a cluster-randomized trial of a Screening and Brief Intervention for heavy drinkers in dental practice are reported. Data were obtained from 103 heavy drinking patients recruited from randomized intervention (7; n = 50) and control (6; n = 53) practices. Analysis of data revealed that 6-month decreases in total drinks per week were significantly (p < .05) greater for heavy drinking intervention (43%) than control patients (21%)—a 4 drink per week difference. Similar decreases were obtained for quantity and frequency among intervention patients compared to control patients. Despite power limitations, the 6-month results support the effectiveness of the Screening and Brief Intervention.