One aim of residential drug treatment programs for drug offenders released from prison is to reduce recidivism rates for these offenders. However, research on this topic has shown mixed results on the effectiveness of such programs, and all of the factors that influence whether an individual will recidivate are still unclear. This study explored the relationship between criminal classification levels of drug offenders and the length of time spent in residential treatment and the effects that this relationship had on drug offenders' odds of recidivism. Data from case history records of drug-involved offenders in Florida from 1991 to 1997 were analyzed to determine whether the length of time in treatment reduced these offenders' odds of recidivism, whether offenders convicted of a felony 1 level offense were more or less likely to recidivate compared to those convicted of a felony 2 or 3 level offense, and whether there was an interaction effect of length of time in treatment and criminal classification level on offenders' odds of recidivism. Binary logistic regression analysis shows that the more time a drug offender spends in residential treatment, the higher the offender's odds of recidivism; drug offenders convicted of a felony 1 level offense were less likely to recidivate than offenders convicted of a felony 2 or 3 level offense; and that there was no interaction effect of length of time spent in treatment and criminal classification level on drug offenders' odds of recidivism. / Master of Science