Serum levels of total cholesterol, high density lipoprotein (HDL) cholesterol, triglyceride, apolipoprotein (apo) AI, ApoB, ApoE and body fat were measured in 226 fasting male Japanese college students aged 18 to 20 years. They were normolipidemic (total cholesterol: 169±31 mg/dl, triglyceride: 56±25 mg/dl) and their HDL cholesterol concentrations were high (61±13 mg/dl). An HDL cholesterol value <35 mg/dl was observed in only one student (0.4%). In contrast, 112 men (49.6%) had an HDL cholesterol level ≥60 mg/dl. Even in this normolipidemic group, as compared with students in a top HDL cholesterol tertile (HDL cholesterol; 75±9 mg/dl), students in a lower HDL cholesterol tertile (HDL cholesterol; 48±5 mg/dl) had significantly increased serum levels of LDL cholesterol (103±30 vs. 91±26 mg/dl), triglyceride (68±30 vs. 45±16 mg/dl) and apoB (83±20 vs 73±17 mg/dl). In addition, they had greater body mass index (23.2±3.6 vs. 20.6±2.5 kg/m 2) and greater percent body fat (20.2±6.2 vs. 16.2±4.2%) determined using a bioelectrical impedance analyzer. HDL cholesterol levels were much more strongly related to triglyceride ( r=−0.37) than was apoAI ( r=−0.13). In stepwise multiple regression analysis in 184 nonsmokers, apoE, apoB and fat mass explained 21% of apoAI variability. Triglyceride in addition to these three parameters explained 41% of HDL cholesterol variability. These results suggest that serum levels of HDL cholesterol are associated with metabolism of apoB-containing lipoproteins as well as triglyceride-body fat interrelationship.