Context: Cadmium is an important predictor of lung function, including forced vital capacity, forced expiratory volume and peak flow. Current evidence supports the notion that cadmium may be an important risk factor for cardiovascular fitness. Objectives: The purpose of this study was to determine the effect of cadmium exposure on cardiovascular fitness in representative sample of US white, blacks and Mexican Americans. The study also sought to determine if the relationship between cadmium and cardiovascular fitness varies by gender and racial/ethnic group. Methods: The data utilized for this study were obtained from National Health and Nutrition Examination Survey (NHANES). One-thousand nine hundred and sixty three subjects with data on cardiovascular fitness were eligible for this investigation. In NHANES, cardiovascular measurements were taken in series consisting of two minutes warm up exercise, two-three minutes exercise testing and two minutes resting period .The goal was to elicit 75% of predetermined age-specific heart rate by the end of the stress test. Cadmium was measured in the laboratory by taking urine sample of participants. Gender and race/ethnic specific multivariate linear regression analyses were performed to determine relationship of urinary cadmium with VO2 max. Results: There were gender and racial/ethnic difference in the relationship between urinary cadmium and VO2 max. In males and females, increased concentration of urinary cadmium was associated with decreased VO2 max across racial/ethnic groups (except in black males. The greatest negative association between cadmium and VO2 max was observed in black females (beta=-0.330) while the lowest value was recorded for white females (Beta=-0.074). The association was statistically significant in white males (Beta=-0.402, P =0.020) and Mexican American females (Beta=-0.290, P=0.026). Conclusion: There was inverse association between urinary cadmium and estimated VO2 max in a US nationally representative sample of White, Black and Mexican Americans. The impact of the gender and racial/ethnic differences in the association between urinary cadmium and VO2 max is not clear and warrants further investigation.