The objective of the study was to evaluate the effectiveness of a computer-delivered intervention (CDI) to reduce heavy drinking and alcohol-related problems in college students in two randomized clinical trials. In Experiment 1, we randomized 144 students to either the CDI or an assessment-only control group with follow-ups at 1 and 12 months. In Experiment 2, we randomized 82 students to either the CDI or a delayed-assessment control group with follow-up at 1 month. In Experiment 1, participants in both groups significantly reduced their drinking at both follow-ups. Compared to the control group, the CDI group reduced their drinking significantly more at 1 and 12 months on three drinking measures at α < .05. Using a more conservative, Bonferroni-adjusted criterion yielded one significant difference in a measure of heavier drinking at the 1 month follow-up. The mean between-groups effect sizes were d = .34 and .36 at 1 and 12 months, respectively. Experiment 2. Compared to the delayed assessment control group, the CDI group significantly reduced (by the Bonferroni-adjusted criterion) their drinking on all consumption measures. These results support the effectiveness of the CDI with heavy drinking college students when used in a clinical setting. In addition, the significant reductions in typical drinking in the control group in Experiment 1 and not in Experiment 2 combined with comparable baseline characteristics suggests that the control group in Experiment 1 demonstrated assessment reactivity.