According to a recent report of the Surgeon General (U.S. Department of Health and Human Services 1999), a range of treatments exist for most mental disorders, and the efficacy of those treatments is well documented. However, a supplement to that report (U.S. Department of Health and Human Services 2001) notes that minorities are largely missing from the efficacy studies that make up the evidence base for treatments. Because of this omission, questions arise as to whether it is appropriate to advocate for providing evidence-based care for minority populations. Do efficacious treatments generalize to minority populations? Should we adapt care for each cultural group? Does poverty affect outcomes of care? If we were better able to encourage ethnic minorities to enter care, would outcomes be similar to those found for majority patients? New data have become available regarding the impact of mental health interventions on ethnic minorities. Although data are not available to answer each question posed above, we examine what is known about outcomes of mental health treatments for ethnic minorities and begin to answer these important questions about providing care to our growing and diverse ethnic minority populations. Outcomes of mental health care are obtained through two types of research, efficacy and effectiveness studies. Efficacy studies, or randomized, controlled trials, are useful in identifying the outcomes that are likely to be associated with precisely defined care provided by experts. These studies identify the impact of interventions on outcomes, such as decreases in psychiatric symptoms and remission of syndromes. The goal of efficacy studies is to determine whether or not an intervention works for a specific syndrome. Thus, the populations studied need to meet criteria for that syndrome and be relatively free of comorbid disorders. Furthermore, highly trained, specialized clinicians provide the care under carefully specified conditions. To date, these studies have predominantly been conducted in nonminority populations; well-controlled efficacy studies examining outcomes of mental health care for minorities are rarely available. In fact, in an analysis conducted for the report of the Surgeon General entitled “Mental Health: Culture, Race and Ethnicity” (U.S. Department of Health and Human Services 2001), it was found that of 9266 participants involved in the efficacy studies forming the major treatment guidelines for bipolar disorder, schizophrenia, depression, and attention deficit/hyperactivity disorder (ADHD), only 561 Black, 99 Latino, 11 Asian American/Pacific Islanders, and zero American Indians/Alaskan Natives were included. Few of these studies had the power necessary to examine the impact of care on specific minorities. In this chapter, we examine available data from treatment outcome studies with minorities. Effectiveness studies are also important when thinking about outcomes of psychosocial interventions because these studies help evaluate outcomes of care given in real-world settings. Once an intervention is found to be efficacious, effectiveness studies then determine how they work within more diverse (both in terms of diagnosis and comorbidities) populations and when given by less-specialized clinicians. Clinicians in effectiveness studies are more likely to be generalists working in clinical settings. Outcomes often include factors such as whether or not care is sought, length of care, and adequacy of interventions. In addition, because of generally larger sample sizes, some of these trials are able to examine outcomes associated with not only symptom reduction, but also with functioning, quality of life, and cost effectiveness of care. Newer studies tend to include more diverse samples and a few have specifically included a minority sample. Again, we examine data available for minorities and compare outcomes with nonminority samples.