A diagnostic dilemma exists at the extreme ends of the spectrum in the cytodiagnosis of hepatocellular carcinoma (HCC). The cytologic features of fine needle aspiration biopsies from 30 well- and 16 poorly differentiated HCC were reviewed and the adjunctive role of serum alpha-fetoprotein (AFP), hepatitis B virus (HBV) markers and radiologic findings evaluated. Some subtle features noted in very well differentiated HCC include small tumor cell size with increased nuclear/cytoplasmic ratio, monotony of atypia, hepatocytic tumor giant cells and narrow trabeculae with tendency for cell dissociation. Useful features in poorly differentiated HCC include cell dehiscence, large cells with ovoid nuclei and thickened nuclear membranes, and one or more increasingly prominent nucleoli, with some assuming a reniform configuration. The serum AFP levels are not always elevated. Positive HBV markers, cirrhosis and compatible imaging findings are suggestive but not diagnostic. The general inclination, however, is still toward a diagnosis of HCC if the aspirate is from a focal lesion or lesions in a hepatitis B surface antigen-positive, cirrhotic liver. Cell block sections provide histologic confirmation.