This paper reports findings from a clinical trial of a probation case management (PCM) intervention for drug-involved women offenders. Participants were randomly assigned to either PCM (n=92) or standard probation (n=91), and followed for 12 months using measures of substance abuse, psychiatric symptoms, social support and service utilization. Arrest data were collected from administrative datasets. The sample (N=183) included mostly African American (57%) and White (20%) women, with a mean age of 34.7 (SD = 9.2) and mean education of 11.6 years (SD = 2.1). Cocaine and heroin were the most frequently reported drugs of abuse, 86% reported prior history of incarceration, and 74% had children. Women assigned to both PCM and standard probation showed change over time in the direction of clinical improvement on 7 of 10 outcomes measured. However, changes observed for the PCM group were no different than those observed for the standard probation group. Higher levels of case management, drug abuse treatment, and probationary supervision may be required to achieve improved outcomes in this population.