Plasma cholesterol was measured in 7,338 participants of a cholesterol screening in Miami, Florida. They were typically health conscious as evidenced by the low prevalence of current cigarette smoking (16%). However, more than 30% of males and 49% of females over age 50 had cholesterol levels in excess of 240 mg/dl, placing them at moderate to high risk for coronary artery disease. Results revealed a dose response relationship between cigarette smoking and cholesterol in men of all age groups and in women of premenopausal age; whereas the average cholesterol was similar in exsmokers and never smokers. Risk analysis revealed a strong positive association between cholesterol and the period prevalence of myocardial infarction in men and women. Male and female patients with newly diagnosed hypercholesterolemia reduced their cholesterol an average of 13 and 10 mg/dl, respectively, under care of a physician. These results indicate that cholesterol screening coupled with physician follow-up and treatment can lower cholesterol and its attendant risk of cardiovascular disease.