This cross-sectional study compared differences in os calcis bone density and distal radius bone mineral content (BMC) among adolescent soccer players, competitive swimmers, and control subjects. Sixty-eight males and females (23 soccer players, 20 swimmers, 25 controls) ages 13 to 17 served as subjects. The results for os calcis trabecular density indicate a trend that may be of clinical significance and that may warrant further study. The swimmers had the lowest os calcis density in both sexes whereas the soccer players had the highest bone density at this weight-bearing site (F=2.54, p<.08). No differences with respect to distal radius BMC were observed among activity groups or between sexes.