Smoking is related to a decreased bone mass and increased risk of osteoporotic fractures. Nevertheless, the effect of smoking in males is poorly understood. The purpose of this study was to assess the repercussion of smoking on bone mass in otherwise healthy male smokers and its relationship with markers of mineral metabolism and hormone profile. We measured bone mineral density (BMD) in 57 healthy males (26 nonsmokers, 31 smokers; aged 20-45 years) by dual X-ray absorptiometry (DXA, Hologic QDR1000) in the lumbar spine and proximal femur. In a subset we measured biochemical markers of bone metabolism and hormonal profile. We found significant differences in BMD between heavy smokers (more than 20 cigarettes/day) and nonsmokers in all skeletal sites. Serum levels of dehydroepiandrosterone sulfate (S-DHEAS) were lower in smokers and correlated with femoral BMD measurements. No significant differences in bone turnover markers were found. Our findings show that smoking by healthy young males is associated with decreased bone mass.