Between 1984 and 1987 1000 consecutive patients with stated or suspected ischemic heart disease underwent selective coronarography and left ventriculography. Patient's age ranged from 23 to 70 years (mean - 47 yrs). Atherosclerotic lesions in three main coronary arteries: left anterior descending, circumflex and right coronary artery were assessed. Stenosis exceeding 50% of a vessel lumen was considered as a significant one. Changes were evaluated in the whole group of patients and in two subgroups in relation to patients age (younger and older than 40 years). Besides assessment of atherosclerotic changes in coronary arteries a presence of IHD risk factors, family occurrence, disease progress and methods of further therapy were analyzed. 60.9% of patients had a documented history of myocardial infarction in the post. Unchanged coronary arteries were found in 77 patients (7.7%), one isolated coronary artery stenosis in 145, single coronary artery stenosis with nonsignificant atherosclerotic lesions in other arteries in 328. Two significantly narrowed arteries were found in 285 patients and 101 subjects had significant changes in three coronary arteries. Analysis of further therapy revealed following results: 520 patients underwent PTCA or CABG (270 - PTCA and 250 - CABG), 439 were conservatively treated and only 41 did not need further cardiological care. Comparing atherosclerotic changes in patients younger and older than 40 years, a statistically significant correlation between patient's age and a number of coronary artery stenosis was stated. Diffuse coronary atherosclerosis more frequently occurred in patients more than 40 years. In youngers changes mainly concern a single coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS)