Introduction: Racial differences in women's regular physical activity are well documented, but explanations are elusive. Characteristics of paid work, specifically control over when and how work is done and schedule control, are frequently overlooked in studies of physical activity habits. Methods: Pedometer data were obtained four-times across a 12-month period from a sample of working mothers of children aged 4 to 9, residing in one North-Central metropolitan area. These data were used to estimate the total number of steps taken per day, and the total number of days where 10,000 or more steps were taken. Job control and schedule control were operationalized using established scales. Results: Black women had lower average steps/day and fewer days with 10,000 or more steps than White women in every season, although the difference was narrowest in winter when White women's physical activity declined. Job control and schedule control are lower for Black than White women, especially among those with low educational attainment, and each is associated with physical activity. Job control explained 4% and 6% of the racial difference in total steps/day for high and low education women, respectively. Schedule control explained 4% and 8% of racial differences in steps/day for high and low education women, respectively. Conclusion: Consistent with calls for greater workplace flexibility, control over work partially explained racial differences in women's physical activity, particularly among women with lower educational attainment. Job control likely supports regular physical activity, particularly among low education Black women who are most at risk for sedentary lifestyles.