The ongoing Prospective Cardiovascular Münster (PROCAM) study was initiated in 1979. The objectives of this trial were to determine the prevalence of coronary heart disease (CHD) risk factors in the German population, improve the prediction and early detection of CHD, and derive recommendations for the primary prevention of vascular disease from the trial results. Of male PROCAM trial participants, ages 40 to 65 years, who had been free of myocardial infarction or stroke at the time of entry and had been followed up for 4 years, longitudinal data analysis shows that hypertension, diabetes mellitus, and hyperlipidemia are independent risk factors for CHD. The concomitant occurrence of these factors leads to a cumulative increase in CHD risk. Hyperlipidemia is a more significant risk factor for CHD than hypertension or diabetes mellitus. Ongoing data from 4043 men and 1333 women, ages 50 to 65 years, show that more than 50% of all diabetics are hypertensive. Cholesterol is slightly increased in male hypertensives and diabetics of either sex, whereas low-density lipoprotein cholesterol is slightly raised in male hypertensives and female diabetics only. The serum triglyceride concentrations are higher for hypertensives and markedly higher for diabetics of both sexes. High-density lipoprotein cholesterol concentrations are decreased in hypertensives, especially in hypertensive women, and even more so in diabetics. The European Consensus Conference for primary prevention of CHD has classified hyperlipidemia into five groups (A to E). For hypertensives, the proportion of patients in group D (cholesterol between 200 and 300 mg/dl and triglyceride levels between 200 and 500 mg/dl) is 20.4% for men and 6.2% for women, about twice as high as those in the control groups. The occurrence of combined (group D) or massive hyperlipidemia (group E: cholesterol greater than 300 mg/dl and/or triglycerides greater than 500 mg/dl) is prevalent in more than 30% of all diabetics: two to three times more frequently than in nondiabetic patients. When concomitant hypertension is included, this prevalence increases to more than 40% for diabetic men. Among those patients endangered by three risk factors, approximately 40% of all men and 60% of all women have the particularly atherogenic combination that includes lowered high-density lipoprotein cholesterol.