OBJECTIVE To implement a brief intervention aimed at reducing abuse of alcohol among adolescents, and to assess its effectiveness. METHODS One thousand 10th-grade students from seven high schools, chosen by random from the roster of all schools in southern Israel, were assigned to intervention and control groups. The intervention, which was based on Botvin's social skills theory, was conducted over 3 days and included dissemination of information, workshops, lectures by guest experts, and activity areas. It was administered by the staff of the high schools and the Psychological Counseling Service in Israel. A self-administered questionnaire was answered anonymously by students in the 10th grade (pretest) and again in the 11th and 12th grades (posttests). It included questions on sociodemographic data, alcohol-related habits, smoking habits, use of illicit drugs, knowledge, and attitudes. Data were collected between 1994 and 1997 with a 76% follow-up rate at 2 years. RESULTS At baseline there was no statistical difference in alcohol consumption between the intervention and control groups. At 1- and 2-year follow-up the rates of alcohol consumption did not change in the intervention group (p > .05) but rose significantly in the control group (p < .001). In multiple regression analysis the variables male gender, positive attitudes, cigarette smoking, availability of illegal drugs, and intervention group were significant predictors of alcohol consumption. CONCLUSIONS The results of this study show the effectiveness of this intervention program, based on reduced alcohol consumption in the intervention group at 1- and 2-year follow-up, compared with the control group. Compared with other programs, the present intervention is brief, intensive, and relatively easy to implement.