The pathological features and diagnostic criteria of hepatocellular carcinoma are described. Tumour cells differentiate in a way similar to that of normal liver cells, in aspects of cytological and histological appearance, growth pattern or production of a biosynthetic product. The morphological and biological features of the tumour, including proliferative indices, DNA ploidy and genetic expression, have been studied. Some of them have shown to provide good prognostic significance and they are discussed. These help to guide the clinicians in the management of patients and in assessment of long-term prognosis.