Mental health professionals have responded to ethnic and racial disparities in mental health care by advocating increasing cultural relevancy in treatment. A central component of cultural relevancy is ethnic and racial pairing of clients and providers. This study examined the effects of client-case manager ethnic and racial matching among white and Hispanic clients who received assertive community treatment in the Access to Community Care and Effective Services and Supports Program. Twelve-month outcomes and service use were examined among 242 Hispanic and 2333 white clients seen in the first 3 years of the program. Analysis of covariance was used to evaluate the association of client-case manager ethnic and racial matching with changes in health status and service use from baseline to 12 months after program entry. At baseline, Hispanics had more serious problems than whites on several measures of psychiatric and substance abuse domains, and they also showed less improvement than whites over the next year on several measures of psychiatric status and service use. One significant association with ethnic matching was found: when treated by a Hispanic clinician, Hispanic clients showed less improvement in symptoms of psychosis. These results do not support the hypothesis that ethnic and racial matching improves outcomes or service use. Several explanations are offered for the results.