Osteoarthritis (OA) is characterized by the degeneration of joints and cartilage, which often compromises a person's range of motion. OA affects health status significantly. There is no cure for OA, and treatment is directed primarily toward pain management. Exercise improves health status in OA patients. However, researchers have had difficulty in developing programs that sustain exercise behavior after interventions are terminated. No study has examined the relationship between exercise behavior and coping styles among individuals with OA. Research suggests that problem-focused coping is more effective than emotion-focused coping in producing long-term health benefits. However, OA sufferers tend to rely on emotion-focused coping. The present thesis was designed to examine the relationship among exercise behavior, problem-focused coping, emotion-focused coping, and social support among individuals with OA. The participants were 269 adults, age 60 and older, from a Southern California health maintenance organization (HMO) who had a diagnosis of osteoarthritis and who were participating in a health intervention study. Exercise behavior was measured from self-reported exercise duration (minutes per week) and frequency (times per week). Folkman and Lazarus' Ways of Coping Questionnaire was used to measure problem-focused and emotion-focused coping. Social support was measured with the Norbeck Social Support Questionnaire, and health status was measured with the Quality of Well-being scale. Moderated mediation analysis using SPSS was used to test the relationships among coping style (predictors), exercise (mediator), social support (moderator), and health status (outcome). It was hypothesized that increases in problem-focused coping, leads to increases in exercise behavior, would produce better health status, and this would vary as a function of social support. It was also hypothesized that there would be a curvilinear relationship between higher levels of emotion-focused coping, exercise, social support, and health status. The results did not support the hypothesis of moderated mediation between coping style, exercise behavior, and social support on health status. However, it did reveal a significant positive relationship between problem-focused coping and exercise duration. The findings also showed social suppor's moderating effects on the relationship between each coping style and health status. When social support was high, more problem-focused coping was associated with better health status. This relationship reversed when social support was low. Less problem-focused coping was associated with better health status. Emotion-focused coping had a curvilinear relationship with health that was moderated by social support. When social support was high, participants with low to moderate levels of emotion-focused coping had better health status than those with high levels of emotion-focused coping. However, this trend reversed when social support was low. Thus results from the study suggest a relationship between exercise and problem-focused coping, but no meditational relationship between the effects of emotion-focused coping and exercise on health status. Social support moderated the linear relationship of problem-focused coping to health status, and it moderated the curvilinear relationship of emotion-focused coping on health status. Limitations and future directions for these findings were also addressed.