This report presents the first national data on the mental health services provided by marriage and family therapists. A sample of 526 therapists from 15 states gave descriptive information on their training, level of experience, and professional practices, along with detailed information on recently completed cases. In addition, 429 of these therapits' clients reported on their satisfaction with treatment and their change in function. The findings indicated that marriage and family therapists treat a wide range of serious mental health and relational problems, that they do so in relatively short-term fashion, that they use individual, couple, and family treatment modalities, that couple and family therapy are briefer than individual therapy, and that client satisfaction and functional improvement are quite high.