Objective: Case management has been widely used as an intervention in the treatment of substance abuse problems. Its effectiveness has been associated with over 450 outcomes, some consistent with case management's traditional functions of linking (treatment tasks) and others typical of treatment outcomes such as substance use (personal functioning). Method: Meta-analyses were conducted on 21 randomized clinical trials in which we compared the efficacy of case management with standard-of-care conditions and active interventions. Characteristics of case managementincluding targeted outcomes, case management model, location on the treatment continuum, and intervention quality-were treated as moderators, as were 2 study features, length of follow-up, and methodological quality. Results: Results showed that case management was efficacious across all targeted outcomes when compared with standard of care (␦ ϭ 0.15, SE ϭ 0.037), although the overall effect was weak. There was a significant difference, F(1, 429) ϭ 25.26, p Ͻ .0001, between case management's effect on treatment task outcomes such as linking with and staying in treatment (␦ 2 ϭ .29, p ϭ .001) and improving individuals' functioning of persons with substance abuse problems in areas such as substance use and HIV risk behaviors (␦ 1 ϭ 0.06, p ϭ .05). Moderator analyses demonstrated that (a) 4 case management models were more effective than standard of care in improving treatment task outcomes and (b) case management was effective either in or out of treatment. Conclusions: Our results demonstrate that case management is effective across a wide range of treatment task outcomes, but more limited in its effectiveness with personal functioning outcomes.