The authors present the results of investigation of liver regeneration after partial parenchyma resection.20 patients (16 females, 4 male) aged 31-67 years were operated on because of metastatic colon cancer (7 cases), cavernous hemangioma (6 cases), hepatocellular carcinoma (1), alveococcosis (2), metastases of malignant melanoma (1), gall bladder carcinoma (1), FNH (1) and mucous cystadenocarcinoma (1). The resection according to anatomical segments by Couinaud were performed. Spiral CTs including liver volumetry were taken before and 30 days after the operation. on the 7-th day after the surgery, liver biopsy was performed and the material was examined under light and electron microscope.There was no postoperative mortality. We observed transient elevation of transaminases, bilirubin levels and decrease of albumin level. Control spiral CT revealed increased liver volume in 15 cases (75 percent). In 16 cases (80 percent), electron microscopy investigations showed regeneration of the liver (mitotic figures).Our material shows that hyperplasia as well as blood vessel and bile duct neogenesis play a very important role in liver regeneration process.