The predicted variation of blood pressure and plasma lipid levels, based on association with body weight, age, cigarette smoking, and oral contraceptive usage was examined in 47,000 self-referred subjects who attended a community program for coronary risk factor screening. In both sexes, blood pressure and plasma lipid (cholesterol and triglyceride) levels were positively correlated with age and body mass index (BMI, kg/m squared). Plasma triglyceride concentrations were positively correlated with cigarette smoking. Partial correlation analysis showed age and BMI to be independently correlated with blood pressure and plasma lipids. Plasma cholesterol and triglyceride levels were correlated with each other independently of the effects of age and BMI. Multiple regression analysis showed age to be a more powerful predictor of blood pressure and plasma lipid levels in females than in males, while BMI was a more powerful predictor of blood pressure and plasma lipid levels in males than in females. Current cigarette smoking did not contribute to the prediction of blood pressure or plasma cholesterol level in either sex, but did predict a 10% higher plasma triglyceride level in both sexes. Oral contraceptive usage did not contribute to the prediction of plasma cholesterol level in multiple regression analysis, but did predict higher plasma triglyceride and blood pressure levels. In view of the high prevalence of overweight people in the Australian community, weight reduction would probably be associated with a significant fall in coronary heart disease risk, particularly in males.