Authors elaborated 35 surgically removed tumors of liver by morphological and biochemical methods. From tumors 5 proved to be hepatocellular adenoma (HCA), 12 to focal nodular hyperplasia (FNH) and 18 to hepatocellular cancer (HCC). On the basis of enzyme histochemical and biochemical examinations, HCA is characterised by "normal" enzyme pattern. By the above method, FNH can be divided into two groups, characterized with "normal" and "abnormal" (tumor-like) enzyme change, while HCC proved to be very heterogeneous. Majority of HCA and FNH cases, according to data gained by flow cytometer, were of diploid DNA content. In majority of HCC cases, DNA diploid was aneuploid, but in three cases normal DNA content was observed. The above mentioned examination revealed several different characteristics of human hepatic tumors, compared to experimentally created tumors of liver.