The Medical Outcomes Study Instrument (MOSI), a 20 item functional health status measure was sent to all women aged 30-40 years (n = 486) in a General Practice (list size 6447). There was a 73% response rate to two mailings. Lower scores on all six dimensions of the MOSI were associated with the number of diagnoses and identified mental illness on the patient summaries, unemployment and with positive scores on the Nottingham Health Profile. In two categories, General Health Perceptions and Mental Health, the scores were lower for those on long-term medication. The paper suggests that the MOSI may be a candidate for Health Status measurement in research and audit in primary care, but further research is required.