Bone mineral content (BMC) and bone mineral density (BMD) were measured by dual-energy X-ray absorptiometry Lunar DPX-NT, SV 4.0 in 23 professional male cyclists (age: 28.5+/-3.9 yr; height: 179+/-6.8 cm; weight: 70.9+/-7.1 kg(-1)). Eight subjects had normal L1-L4 T-score values (-0.19+/-0.62) and 15 had low values (-1.57+/-0.45). Correlations between: L1-L4 T-scores and body weight, fat mass (FM) and % FM (r=0.40, p<0.05; r=0.65, p<0.001; r=0.59, p<0.01). Regression analysis: L1-L4 T-score and FM (R2=0.42; p<0.001); total BMC and fat-free mass (FFM) (R2=0.60; p<0.0001); and total BMD and BMI (R2=0.25; p<0.05). Climbers had lower arms BMD (0.85+/-0.04; p<0.05). Flat-terrain cyclist had lower right leg FFM (9.7+/-0.8 kg; p<0.05). Time trialists had higher body weight (76.7+/-4.4 kg; p<0.05), total FFM (68.3+/-4.7 kg), total BMC (3.1+/-0.3; p<0.03), right and left leg BMC (0.60+/-0.1; 0.60+/-0.1; p<0.05), and spinal BMD (1.09+/-0.1; p<0.05). In conclusion, two-thirds of professional cyclists had abnormally low BMD values.