We examined the personal models of osteoarthritis (OA) of 61 patients over 60 years of age. Models were elicited using a structured interview. Shared beliefs included perceiving OA as a serious, painful, chronic, and incurable condition that can be managed by recommended medical treatment. Considerable individual differences were found on six personal-model constructs: Symptoms, Seriousness, Cause, Control, Helpfulness of Treatment, and Negative Feelings about Treatment. The constructs of Symptoms and Seriousness were consistently related to a variety of important outcomes. For example, participants with higher scores on Symptoms and Seriousness reported higher levels of self-management (both concurrently and prospectively), reported more utilization of medical services, and experienced a poorer quality of life. The implications for the design of health-education materials and for patient-provider interactions are discussed.