This study was designed to compare outcomes for two groups of alcohol and substance abuse clients (N=230): a control group assigned to regular 90 days of outpatient treatment, and an experimental group assigned to 180 days of extended outpatient care. Outcomes were compared in the following nine categories: (1) relapse, measured as reported alcohol or drug use subsequent to treatment; (2) post-treatment employment; (3) living arrangements; (4) medical and physical problems; (5) psychiatric problems; (6) legal or criminal justice system problems; (7) family and social relationships; (8) treatment re-entry; and (9) participation in 12-step or other support programs. The major focus of the study was to determine if the additional 90 days of outpatient treatment impacted post-treatment outcome. While the results of the primary analyses were not positive, the findings consistently suggest that extended outpatient treatment, regardless of whether it is the scheduled treatment received by both controls and experiments, or the unscheduled treatment received by either group, is associated with some positive outcomes. From the analyses of both the 90 and 180 days follow up surveys, there are few consistent findings on the impact of extended outpatient care for the nine client outcome areas studied. The principal conclusion is that overwhelmingly, there is no major difference between 90 day treatment or 180 day treatment. Eight appendices present statistical analyses and other materials related to the study. Contains 39 references. (TS)