It has been proposed that diffuse coronary atherosclerosis influences the myocardial perfusion. We performed a study of 94 young men with previous myocardial infarction in order to find out whether the presence and extent of diffuse coronary atherosclerosis affected the relation between maximal stenosis and myocardial perfusion in areas remote from the infarction. The patients were examined by planar-imaging thallium-201 scintigraphy, following exercise, and coronary angiography within 6 months after myocardial infarction. The maximal distinct stenosis and diffuse coronary atherosclerosis, comprising both plaque size and extent, were semiquantitatively assessed. The correlation coefficients between maximal stenosis within the LAD, RCA, and LCX vascular territories and the corresponding initial uptake of thallium were 0.52 (P = 0.0001), 0.30 (P = 0.04), and 0.46 (P = 0.02), respectively. No change of the correlations was found, except for a slight increase of the r-value from 0.30 to 0.37 in regions corresponding to RCA, after controlling for the diffuse atherosclerosis score in a multiple stepwise regression analysis. These findings indicate no impact of diffuse coronary atherosclerosis on regional myocardial perfusion in areas remote from the infarction.