The aim of this study was to broaden the relatively small number of qualitative and quantitative data available on the endothelium of human blood vessels by scanning electron microscopy (SEM) imaging and computer based image analysis of the human endothelial microstructure and dimensions. Endothelium of the arterial blood vessels (common iliac artery and hepatic artery) was imaged directly by using SEM. From high quality images, precise information on the microstructure and dimensions of endothelial cells was obtained by using GIMP and Leica QWin image analysis software. The mean endothelial cell width, length, and area of common iliac artery endothelial cells were found to be 13.2 ± 4.1 µm, 25.8 ± 8.5 µm, and 245.0 ± 115.1 µm2, respectively. For hepatic artery endothelial cells, mean values of cell width, length, and area were found to be 4.9 ± 1.5 µm, 21.9 ± 6.6 µm, and 70.7 ± 34.8 µm2, respectively. Morphology and dimension of the endothelial cells were different depending on the donor, type, and diameter of the arteries due to the effect of blood flow direction and volume rate. The presented method is useful for obtaining quantitative data on human endothelial cells. This study provides a first basis for future studies with larger numbers of samples on morphological changes secondary to pathological conditions, such as hypertension and atherosclerosis. Furthermore, the data may support the development of a template for a novel artificial vascular graft with superior performance.