The paper describes the procedure to prepare endothelial cell monolayer samples from the vascular intima, which is suitable for studying various morphological processes. To obtain high-quality multicellular specimens, it is recommended to preliminarily remove excess tissue from the outside of the vessel and to free the intima; ways to dry the surface and to separate endothelial cells are examined. The paper gives the figures of specimens stained by the Romanowsky-Giemsa method and identifies factor VIII, an endothelial marker, and Chlamydia pneumoniae inclusions in the cytoplasm of endothelial cells.