The aim of this study was to explore the relationship between maximal oxygen consumption (VO2 max) and bone mineral density (BMD) in a group of young Lebanese adults. Twenty women and 37 men whose ages range from 18 to 32 yr participated in this study. Informed written consent was obtained from the participants. Body weight and height were measured, and body mass index was calculated. VO2 max was determined by direct measurement while exercising on a bicycle ergometer (Siemens-Elema RE 820; Rodby Elektronik AB, Enhorna, Sweden). Whole body bone mineral content (WB BMC), whole body bone mineral density (WB BMD), lumbar spine BMD (L1-L4 BMD), total hip BMD (TH BMD), and femoral neck BMD (FN BMD) were measured by dual-energy X-ray absorptiometry. In women, VO2 max (expressed as L/mn) was positively correlated to WB BMC (r = 0.82; p < 0.001), WB BMD (r = 0.80; p < 0.001), L1-L4 BMD (r = 0.73; p < 0.001), TH BMD (r = 0.80; p < 0.001), and FN BMD (r = 0.85; p < 0.001). In men, VO2 max (expressed as L/mn) was positively correlated to WB BMC (r = 0.57; p < 0.001), WB BMD (r = 0.53; p < 0.001), L1-L4 BMD (r = 0.50; p < 0.001), TH BMD (r = 0.38; p < 0.01), and FN BMD (r = 0.30; p < 0.05). In both sexes, the positive associations between VO2 max and bone variables (BMC and BMD) remained significant after adjustment for age (p < 0.001). This study suggests that VO2 max (L/mn) is a positive determinant of BMC and BMD in young adults. Aerobic power seems to be a determinant of BMC and BMD in young adults.