Abstract： Objective To observe the characteristics of coronary microvascular lesions (CML) in the au topsied elderly cases with hypertensive left ventricular hypertrophy (LVH) and t he difference of CML among the groups of essential hypertension (EHT), coronary heart disease(CHD) and diabetes(NIDDM) also with LVH.Methods A retrospective study was performed in 206 cases≥60 years old of EHT, CHD and N IDDM with LVH and 30 normal cases as control, out of 3195 consecutive autopsied cases from 1954 to 1996 in our hospital. Arterioles with diameters of 10-60 μm and capillaries in the muscular layer were shown by the methods of HE, Ela stic fiber +VG staining and immunohistochemistry of CD31. Quantitative measurem ents on the arteriole density (AD), the ratio of arteriolar wall and cavity (RWC ), capillary density (CD) and the area of endothelial cell (AEC) were performe d with light microscope observation and image analysis by computer. According t o the thickness of the left ventricle free wall, the severity of LVH was divided into four degrees from 0 to Ⅲ. LVH of degree 0-Ⅲ was observed in EHT group, while only LVH of degree Ⅰ was found in CHD, EHT+CHD, and NIDDM groups. SAS system was used for statistical analysis. Results AD and RWC increased while CD and AEC decreased significantly with the progressi on of LVH in EHT groups (P<0.05-0.01). There was a similar but more sever e change in the (HT+CHD) group (P<0.01); the AD increased (P<0.05) wh ile all other measurements did not show obvious changes in the CHD group. The A D increased, CD and AEC decreased (all P<0.05), but RWC did not change very much in the NIDDM group. Conclusion CML in the EHT group was characterized by an increased AD and RWC, decreased CD and AEC, among which the increased RWC was the typical change in EHT groups com pared with the groups of CHD and NIDDM. Damaged CML may be one of the main fact ors for decreased coronary flow reserve and myocardial ischemia in cases of EHT with LVH.