The self-reported family support and stress of 249 ambulatory adult patients, aged 18-49 years, were studied relative to their self-reported functional health. Support from family members was found to be related positively with emotional function. Stress from family members was associated negatively with symptom status, physical function, and emotional function. Patients' severity of illness was related negatively to their symptom status, physical function, and social function, but not to their emotional function. During the study a new self-report instrument, the Duke Social Support and Stress Scale (DUSOCS), was developed to measure family and non-family support and stress. Also, a new chart audit methodology, the Duke Severity of Illness Scale (DUSOI), was designed to assess severity in the ambulatory setting. Reliability and validity of the DUSOCS and the DUSOI were supported. The importance of the patient's perception of health and its family determinants is emphasized.