Objectives: This study investigated the effect of weight loss and weight regain on accuracy of perceived exertion (APE) in previously overweight African American (AA) and European American (EA) women. Methods: Formerly overweight women (n=102, age 20-44 years) completed a weight loss program to achieve BMI<25 kg/m2. Physiological variable of exertion and rating of perceived exertion (RPE, Borg's 6-20 Scale) were recorded during submaximal aerobic exercise prior to, immediately following, and approximately 1 year after weight loss. APE was defined as the composite score of physiological variables (heart rate, ventilation rate, and respiratory exchange ratio) minus RPE. Results: APE was significantly different from the composite score of physiological variables at baseline and at 1-year follow-up for EA women (0.347±0.88 P<0.05 and 0.53±0.92, P<0.01, respectively) and at 1-year follow-up for AA (-0.37±1.1, P<0.01). EA women had lower physiological effort at baseline and 1-year follow-up states (-0.24±0.66 P<0.05; and, -0.27±0.84 P<0.05, respectively). AA women had higher physiological effort, at 1-year follow-up state (0.21±0.61, P<0.01). Conclusions: Physiologic effort and perceived exertion contributed independently to the racial differences in APE, and APE may be an important trait to evaluate before planning an exercise intervention.