This study examines the effects of drug abuse treatment on the behavior of drug-involved offenders during incarceration and offender characteristics associated with rule violations. Participants included 170 prerelease inmates with histories of drug abuse who were randomly assigned to either weekly cognitive-behavioral counseling or brief monthly supportive counseling for a 6-month period. During this period, three outcomes were examined: reclassification to greater security, self-reported commission of major rule violations, and citations received for these rule violations. Results of multivariate analyses indicated that cognitive-behavioral treatment was associated with reduced likelihood of reclassification to more secure facilities. Aspects of psychological functioning were also related to reclassification as well as to citations for major infractions.