The purpose of this study was to compare the dietary habits, nutrient intake, bone mineral density(BMD) and bone metabolism in Korean male collegians as related to smoking situation. One hundred sixty one young adult males at the age of 20-26 participated in this study. The subjects were divided into four groups: non smoker(n=42), light smoker(n=34), moderate smoker(n=49) and heavy smoker(n=36). The anthropometric characteristics, smoking situations, dietary habits and nutrient intakes were observed. Bone status of the calcaneus was measured by using quantitative ultrasound(QUS). Bone metabolism markers including serum alkaline phosphatase activity(ALP) and N-mid osteocalcin(OC) were analyzed. There were no significant differences in height, weight, BMI, energy and calcium intake among the four groups. Iron intake of moderate and heavy smoker was significantly lower than that of light smoker. Heavy smokers consumed significantly lower vitamin C than moderate smokers, and their coffee consumption and lifetime alcohol consumption were significantly highest among the 4 groups. QUS parameters and serum ALP were not significantly different among the four groups. Serum OC levels were significantly lower in heavy and non smoker group compared to the moderate smoker group. In conclusion, heavy smokers in young male collegians had undesirable lifestyle and dietary habits, like as high consumption of coffee and alcohol, and low intake of Fe and vitamin C. Although, there was no significant difference in their current bone status from the other groups, these undesirable factors with heavy smoking may affect their bone health in the long term.