The prevalence of coronary heart disease was determined by a conducted survey in a random sample of 3689 subjects 20 years of age or older in 59 communities representing the Turkish adult population. Interview with a questionnaire, physical examination of the cardiovascular system and recording of a 12-lead ECG were performed. The latter was coded according to the Minnesota code. Expressed in age-adjusted rates (for 35-64 years), prevalence rates per 100 men were as follows: typical angina 3.7, atypical angina 0.9, electrocardiographic evidence of myocardial infarction and/or ischemia 3.7, any of the stated findings suggesting coronary heart disease 8. Women had a substantially higher rate of atypical angina, positive ECG findings and of any of the stated manifestations for coronary heart disease, whereas they had a significantly lower rate of Q/QS patterns as well as of a history of myocardial infarction. Based on a probability-related point score, age-adjusted clinical coronary heart disease was estimated to prevail in 5.8% of men and 5% of women (P > 0.4) in the sample of the Turkish population. The respective rates in urban residents was 6% and in rural resident 4.8%. Among participants diagnosed coronary heart disease, 63% presented the form of angina without infarction, 27% had evidence of myocardial infarction, 7% 'silent myocardial ischemia' and 3% cardiac failure alone.