1. The relationship of cigarette smoking with blood pressure and serum lipids and lipoproteins was studied in 1062 young Japanese women aged 20-39 years of age. 2. After adjusting for age, body mass index (BMI), alcohol intake and physical activity scores, the mean systolic and diastolic blood pressures (SBP and DBP, respectively) did not indicate dose-dependent relationships with cigarette smoking. The largest significant mean differences in SBP (3.5%; P < 0.001), DBP (6.2%; P < 0.018), high-density lipoprotein-cholesterol (HDL-C; 13.2%; P < 0.005), ratio of total cholesterol to HDL-C (13.9%; P < 0.022), triglycerides (TG; 24.1%; P < 0.001) and the logarithmic transformation of TG (log TG; 5.6%; P < 0.001) were found between non-smokers and smokers. 3. When age, BMI, alcohol intake and physical activity scores were included in the forward step-wise multiple regression analysis, there were negative relationships found for cigarette smoking and SBP and DBP and positive relationships for cigarette smoking and TG and log TG. 4. Although the results are somewhat variable, the present study shows that cigarette smoking is negatively associated with SBP and DBP and that there is an association between cigarette smoking and serum lipids and lipoproteins and that smoking has an unfavourable effect on these parameters in young Japanese women.