We investigated the relationship among social support, stress and functional status in 439 patients with osteoarthritis (OA). OA is among the most prevalent diseases affecting American adults and is a major contributor to functional impairment, morbidity, and utilization of health care resources. This study examines whether the impact of social support upon health was direct or indirect (i.e. it was present only when respondents were exposed to stressors). We also wanted to explore the relationship between functional status and specific dimensions of support (i.e. self-esteem, appraisal, belonging, and tangible support). Functional status (psychological disability, physical disability, pain) was assessed with the Arthritis Impact Measurement Scales (AIMS). Multiple regression suggested that exposure to stressors and low self-esteem support were associated with increased disability along all AIMS dimensions; appraisal support was not correlated with any AIMS score. Also, physical disability was associated with being older and having less tangible support (R2 = 0.17); psychological disability with being younger, caucasian, and having less belonging support (R2 = 0.47); and pain with being younger, caucasian and having less education (R2 = 0.15). In no instance was there empirical support for the buffering model. Self-esteem appeared to be the most, and appraisal the least, consistent social support dimension when predicting functional status. While exposure to stressors negatively affected all AIMS dimensions, its impact was greatest with respect to psychological disability. We conclude that social support had a direct, rather than indirect, impact on functional status. Future research should consider separately the impact of distinct social support dimensions.