The Transitional Case Management (TCM) study, one of the projects of the Criminal Justice Drug Abuse Treatment Studies (CJ-DATS) cooperative, was a multi-site randomized test of whether a strengths-based case management intervention provided during an inmate's transition from incarceration to the community increases participation in community substance abuse treatment, enhances access to needed social services, and improves drug use and crime outcomes. As in many intervention studies, TCM experienced a relatively large percentage of treatment-group participants who attended few or no scheduled sessions. The paper discusses issues with regard to participation in community case management sessions, examines patterns of session attendance among TCM participants, and analyzes client and case manager characteristics that are associated with number of sessions attended and with patterns of attendance. The average number of sessions (out of 12) attended was 5.7. Few client or case manager characteristics were found to be significantly related to session attendance. Clinical and research implications of the findings and of adherence in case management generally are discussed.