The associations of life-style variables, namely type of dietary fat, alcohol use, smoking, obesity, physical activity and oral contraceptive use with serum lipids, insulin and blood pressure were studied in 1398 adolescents and young adults aged 15-24 years. Smokers were more often physically inactive and regular users of alcohol compared to non-smokers. In females, smoking and alcohol use were more prevalent among oral contraceptive users. Independent effects of life-style variables on lipids, blood pressure and insulin were assessed with multiple linear regression models. In both sexes, body mass index was positively related to low density lipoprotein cholesterol (LDL-C), triglycerides (TG), systolic (SBP) and diastolic (DBP) blood pressure and insulin, and negatively with high density lipoprotein cholesterol (HDL-C). Leisure time physical activity was associated with lower levels of insulin among males. Smoking was related with 0.07 mmol/l lower HDL-C levels and about 0.09 mmol/l higher TG levels in males. In both sexes, smoking was related with lower levels of SBP. In males, alcohol use was associated with 0.05 mmol/l higher level of HDL-C (P = 0.06). In females, alcohol use was associated with lower levels of LDL-C and TG. Oral contraceptive use was associated with approximately 0.15 mmol/l higher levels of TG and about 4.0 mmHg higher SBP. Preferring butter over margarine as dietary fat was associated with 0.26 and 0.19 mmol/l higher levels of LDL-C in males and females, respectively. Accumulation of adverse life-habits contributed to the clustering of an atherogenic lipid profile and high blood pressure. In males, those with 4 selected life-habits present, namely obesity, smoking, inactivity and the use of butter, had 5.5 times greater risk (95% confidence interval 1.4-20.7) of belonging to the group with high LDL-C, low HDL-C and high DBP compared to those with zero or one life-habits present. These data demonstrate that life-habits show clustering in adolescents and young adults. Individuals with many adverse life-style risk factors present are at increased risk of having an atherogenic lipid and blood pressure profile.