Two-thirds of the offenders had no record of a prior arrest, and most of the offenders faced only one charge; most were arrested for possession or use of marijuana; and 43 percent of the offenders were rearrested during the follow-up period. Recidivism was defined as a subsequent arrest for any charge other than a moving violation traffic charge. Eligibility for diversion was limited to those offenders who had no prior felony conviction for any drug offense, had no prior misdemeanor conviction for any drug offense within the past year, had no other felony charges pending, and had not previously been diverted to treatment. The treatment program was designed to reduce subsequent drug use. Although the four drug-specific programs varied in duration, objectives, and methods on the basis of the type and severity of the offender's drug use, each program involved some combination of random drug testing and an educational seminar. The analysis focused on estimating the effects on the time to rearrest of participation in the treatment program, controlling for selected offender characteristics and offense type. Results indicate that offenders who entered and completed treatment fared significantly better than those who entered and failed to complete treatment; and both groups (those who completed and those who failed to complete treatment) performed significantly better than those who were eligible for diversion but who failed to enter treatment. 4 figures, 2 tables and 65 references