BACKGROUND:The interrelations between various physical activity domains have received little empirical attention in the United States. Of particular interest, given the potential applicability to traditionally underserved communities, is the nature of the association between occupational physical activity (OPA) and leisure-time physical activity (LTPA). METHODS:5448 adult men and women who participated in NHANES 1999-2000 were included in analyses. Linear regression was used to examine the bivariate and multivariable associations of OPA and education with LTPA. Generalized logit models were used to examine the association of education with OPA. RESULTS:We found no association between education and LTPA. OPA was significantly positively associated with LTPA (P < .001). The association between OPA and LTPA was not strongest among those with low education and held only for men in gender-stratified analysis. Education was inversely associated with OPA (P < .001) in multivariable analysis. CONCLUSIONS:Our findings lend preliminary support to the hypothesis that OPA is an important determinant of LTPA, particularly in men. This provides additional support to calls for assessment of OPA, particularly among individuals of low social class.