This article provides a summary of effectiveness research on the costs of including family therapy in mental health services. Data was available from four different sources: 1) a large western Health Maintenance Organization with 180,000 subscribers in the local Utah region; 2) the Medicaid system of the entire State of Kansas in the United States; 3) a US health insurance company with several million subscribers; and 4) a Family Therapy training clinic. Results suggest that family therapy reduces the number of health care visits, especially for high utilizers. These results were also replicated in a graduate student training clinic. Also, studies of two different health care systems (and a cost projection study) suggest that including family therapy as a treatment option does not significantly increase health care costs.