The relationship between the frequency (chronic, episodic, and sporadic) of arthritic pain in the hip and/or knee, other illness-related variables, physical disability, and a physically active lifestyle was analyzed in community-living subjects aged 55 to 74 years (N = 306). We tested the hypothesis that a physically active lifestyle is a mediating variable in the relationship between pain frequency and physical disability. Physical activity was measured with a structured interview method, and physical disability was measured with the Sickness Impact Profile. A stepwise regression model with demographic data, pain frequency, illness-related variables (such as radiological osteoarthritis and pain severity), and lifestyle variables explained 45% of the variance in physical disability; lifestyle variables explained 7% of the variance in physical disability. Our results support the hypothesis that a physically active lifestyle (in particular, sport activity) is a mediator in the relation between the frequency of pain and physical disability.