Commitment is a self-control technique to induce weight loss. Tow targets of commitment contingencies, completion of the study and behavior change, were examined among 42 female and 3 male subjects who made a monetary deposit to enroll in the 10-week program. The treatment consisted of self-monitoring of eating and exercise behavior. Subjects were randomly assigned to one of three treatment groups: (1) no commitment; (2) study completion commitment; and (3) study completion plus behavior change. Attrition, three measures of study participation, behavior change, and short- and long-term weight loss were evaluated. The no-commitment group had the greatest attrition rate. Only one participation variable was affected; the behavior change commitment increased the frequency of self-monitoring, and resulted in greater change in eating behavior but did not affect change in exercise behavior. The number of weigh-ins attended and frequency of self-monitoring were positively related to weight loss. Change in exercise behavior predicted weight loss; change in eating did not. Commitment contingencies have a narrow effect in a weight loss program and little generalization to non-targeted behavior occurs. (Author/NRB)