Objective: As there are theoretical, clinical, and "common sense" reasons to expect a relationship between organizational factors and outcome in clinics providing psychotherapy and other mental health treatments, a review of empirical research in this area was undertaken with the aim of finding empirical evidence for organizational effects. Methods: A structured search for studies on organizational differences in patient mental health outcomes was performed using EBSCO host, Cochrane Library Database, and the Health Systems Evidence database at McMasters University. Finished studies published in English were included if they presented data from more than one mental health service and used change in symptom, level of functioning, or quality of life as outcome. Results: The search yielded not more than 19 studies fulfilling inclusion criteria. All studies showed some evidence for organization effects, and there was some evidence for organizational climate and culture explaining differences in outcome. Conclusion: Given that mental health treatments are likely to be especially susceptive to organizational effects, it is remarkable that not more research has been devoted to this. Clearly, more research is needed to study the consequences of work organization for the outcome of psychotherapy. Methodological issues in organizational studies are discussed.