Physical activity levels, which have a direct relationship to fitness levels and future morbidity and mortality, have been shown to differ based on ethnicity. White children report higher levels of physical activity than their African American or Hispanic counterparts. In previous research, we have demonstrated significant cross-cultural differences among elementary students' fitness levels. The purpose of this study was to determine the relationship between self-reported activity levels, students' perception of their own fitness, self-efficacy regarding exercise, and actual fitness scores in 4th and 5th grade students. The study population consisted of 612 students drawn from schools in a large Midwestern city and suburb. Students were given the Fitnessgram® fitness test and completed a 46-item questionnaire. 432 students (African American, n=95; Hispanic, n=76; White, n=261) completed all aspects of the study and were used in the final analysis. Pearson product moment correlations were run between eight of the questions designed to elicit responses regarding activity levels, perceptions of fitness, and self-efficacy regarding exercise, and seven measures of health related fitness. Significance was set at p<0.05. In African American students, significant negative correlations were found between time spent in cardiovascular activity and push-ups, between self-efficacy and the mile run, and self-efficacy and BMI. In addition, significant positive correlations were found between self-efficacy and sit and reach right and left and self-efficacy and push-ups. In the Hispanic population, there was a positive correlation between self-efficacy and sit and reach right and left, push-ups, and trunk lift. In Whites, there were significant positive correlations between self-reported cardiovascular activity and self-perception of fitness levels and the dependent fitness variable mile run. There were also significant positive correlations between self-efficacy and push-ups, while self-efficacy was negatively correlated with the mile run and BMI. In conclusion, self-efficacy is correlated to measured fitness levels in White and African American students but not Hispanic students. Only White students were found to have an accurate perception of their own fitness levels and were the only ethnic group whose self-reported activity levels correlated with their fitness scores. The results of this investigation may be used to design interventions specific to each ethnic group, to promote physical activity, and to reduce the risk of morbidity and mortality associated with low fitness levels.