The Washington State Mental Health Outcome Study was intended (a) to collect descriptive data on the status of a cross-sectional sample of the client caseload in state mental health centers, and descriptive data on'the change between admission and 90-day follow-up of a sample of new admissions to the centers, and (b) to test the feasibility of state-wide mental health outcome studies. Results show highly significant changes between pre- and post-treatment interviews, although since there is no control group the changes cannot be attributed to the treatment programs. The data have been used by state level mental health administrators in presentations to the legislature and to community groups. The Washington strategy is compared with two other approaches to state-wide mental health outcome.