OBJECTIVE To assess the benefits of matching alcohol dependent clients to three different treatments with reference to a variety of client attributes. METHODS Two parallel but independent randomized clinical trials were conducted, one with alcohol dependent clients receiving outpatient therapy (N = 952; 72% male) and one with clients receiving aftercare therapy following inpatient or day hospital treatment (N = 774; 80% male). Clients were randomly assigned to one of three 12-week, manual-guided, individually delivered treatments: Cognitive Behavioral Coping Skills Therapy, Motivational Enhancement Therapy or Twelve-Step Facilitation Therapy. Clients were then monitored over a 1-year posttreatment period. Individual differences in response to treatment were modeled as a latent growth process and evaluated for 10 primary matching variables and 16 contrasts specified a priori. The primary outcome measures were percent days abstinent and drinks per drinking day during the 1-year posttreatment period. RESULTS Clients attended on average two-thirds of treatment sessions offered, indicating that substantial amounts of treatment were delivered, and research follow-up rates exceeded 90% of living subjects interviewed at the 1-year posttreatment assessment. Significant and sustained improvements in drinking outcomes were achieved from baseline to 1-year posttreatment by the clients assigned to each of these well-defined and individually delivered psychosocial treatments. There was little difference in outcomes by type of treatment. Only one attribute, psychiatric severity, demonstrated a significant attribute by treatment interaction: In the outpatient study, clients low in psychiatric severity had more abstinent days after 12-step facilitation treatment than after cognitive behavioral therapy. Neither treatment was clearly superior for clients with higher levels of psychiatric severity. Two other attributes showed time-dependent matching effects: motivation among outpatients and meaning-seeking among aftercare clients. Client attributes of motivational readiness, network support for drinking, alcohol involvement, gender, psychiatric severity and sociopathy were prognostic of drinking outcomes over time. CONCLUSIONS The findings suggest that psychiatric severity should be considered when assigning clients to outpatient therapies. The lack of other robust matching effects suggests that, aside from psychiatric severity, providers need not take these client characteristics into account when triaging clients to one or the other of these three individually delivered treatment approaches, despite their different treatment philosophies.