220 trained men, examined the day before participation in a cross country skirace, had significantly higher HDL-cholesterol and HDL-/total cholesterol ratio than untrained men, but did not differ significantly from untrained women. HDL-cholesterol was significantly higher in skiers above 60 years than in skiers of younger age. Tobacco smokers had lower HDL-cholesterol and HDL-/total cholesterol ratio than non-smokers, but the differences were only significant in skiers, not in controls. HDL-cholesterol was positively correlated to total cholesterol in skiers. The higher HDL-cholesterol level may possibly contribute to the lower morbidity of CHD in men who are physically active during leisure time.