Objective. To study possible vessel-related complications of liver regeneration after tangential liver resection in the experiment. Methods. Features of post-resection liver regeneration caused by vascular damage were studied by using of light microscopy. Results. Fibrous connective tissue at the site of vascular injury was observed in 1 week after surgery. Parenchyma near the scar sometimes contained the debris surrounded by leukocytes and fibroblasts. Long and thick layers of connective tissue formed at the site of cut and non-functioning vessels and bile ducts were directed from sites with debris into the depth of liver. Two weeks later connective tissue scar with high content of macrophages was located on the liver surface and there were many cells with intensive brown coloring of cytoplasm (apparently, siderophages or cells containing bile components). In certain cases the liver was deformed by connective tissue strangulations up to 200 microns which most likely was formed by vessels. In the subsequent terms the organ structure was practically restored in the majority of rats. However, in approximately 1/3 of animals thick layers of dense fibrous connective tissue containing many leukocytes and groups of large cells with brown cytoplasm were directed from the place of resection into parenchyma. Conclusion. Active processes of damage and sclerosis of the organ due to vascular disorders continued even 5 weeks later after liver resection in some rats. This can result atrophy or fibrosis of entire lobe. Injury of large vessels and bile ducts should be prevented during liver surgery whenever it is possible. It is advisable to maintain and preserve remnant liver function up to its complete compensatory hypertrophy.