This study compared perceived exercise self-efficacy, exercise benefits, exercise barriers, and commitment to a plan for exercise between Korean women with a diagnosis of either osteoporosis or osteoarthritis. The influence of exercise self-efficacy, exercise benefits and barriers on commitment to a plan for exercise was also assessed in each group. Participants in the study were 154 Korean women over 40 years of age who were recruited from hospitals, health centers or a nursing home. The two groups differed on commitment to a plan for exercise with commitment greater among women with osteoporosis. Exercise self-efficacy was the most influential variable on commitment to a plan for exercise accounting for 27% of the variance in commitment among osteoporosis patients and 53% of the variance among osteoarthritis patients. This study generated information relevant to tailoring exercise interventions to the differing needs and perceptions of Korean women with osteoporosis and osteoarthritis.