Based on the assumption that truancy is a discrete form of behavior alterable by manipulation, rather than just a symptom of some underlying problem, an experiment among ninth graders investigated the effect of contingency management (using rewards to effect behavior changes) on truancy. Identification of habitual truants to participate in the study was made during the first phase. In the second phase, participants were subjected to the treatment, contingency management, which consisted of a contract between participants and the school counselor for each participant to have daily class attendance based on a specially formulated reward schedule. In the third phase, the reward system was replaced by group meetings at which attendance and related topics were discussed. In the fourth phase, instead of rewards or conferences, only regular school policy on truancy governed class attendance. Results showed a statistically significant, steady decline in truancy among participants through all phases of the study, while a control group demonstrated no truancy decline. It was suggested that the behavior modification techniques in the second and third phases influenced truancy reduction in the experimental group. In the last phase, the truancy rate was higher for the control group than for the experimental group, but the difference was not statistically significant. (MJL)