In the Honolulu Heart Program, 11,148 men were identified of whom 8,006 participated in baseline examinations between 1965 and 1968. The 1965 - 1968 examination included a detailed medical and social history with specific inquiries about smoking, alcohol consumption, diet, and physical activity. A physical examination focussed on the cardiovascular system; laboratory tests included hematocrit, serum cholesterol, triglyceride, uric acid, glucose determination, and urinalysis. A twelve lead electrocardiogram and lung function testing revealed that 301 men had evidence of coronary heart disease and 111 had a stroke. The prevalence of coronary heart disease was slightly higher than in the comparable population in Japan, but the incidence rate during the first two-year period of follow-up was twice as high in Honolulu as in Japan. Stroke prevalence was much higher in Japan than in the Honolulu cohort, with a threefold difference. The Honolulu Japanese men were more obese, ate a more Westernized diet with a higher amount of animal protein, saturated fat, and sucrose and a smaller amount of complex carbohydrates. They had higher levels of serum cholesterol, triglyceride, uric acid, and glucose than Japanese men in Japan. Cigarette smoking was more common in the Japanese cohort, while the proportion of heavy smokers was greater in the Honolulu cohort. Alcohol consumption in the Japanese cohort was twice that of the Honolulu cohort. There were no differences in mean blood pressure or prevalence of hypertension. Repeat examinations were performed near the second and sixth anniversaries of the initial examinations. The six year follow-up data identified 294 new cases of coronary heart disease and 133 new cases of stroke. Between 1970 and 1972 some 2,800 of the cohort were examined and had lipoprotein determinations performed as part of the NHLBI Lipoprotein Phenotyping Project. Survivors of the lipoprotein cohort were reexamined between 1975 and 1978 near the tenth anniversary of their initial examination and again between 1980 and 1982.