The DNA content of 12 small hepatocellular carcinomas (SHCC, less than 3 cm in diameter) and 26 large hepatocellular carcinomas (LHCC) was quantitatively determined by means of TV-image analysis. The results showed that 8 patients (66.7%) with SHCC had DNA stem lines in diploid (2C), and 24 (92.3%) with LHCC had DNA stem lines in aneuploid (AN) (P less than 0.01). The incidences of tumor capsule breaking and cancerous thrombosis were 16% and 20% respectively in SHCC, significantly lower than 84% and 80% in LHCC (P less than 0.01). The 5-year survival rate was 75% in patients with SHCC after operation, much higher than 46.2% in patients with LHCC. No relations were found between DNA content, tumor size, pathological grading and serum AFP values of HCC. The results suggest that SHCC less than 3 cm in diameter reflects the early changes of biological characteristics; HCC of 3 cm in size may be at an important period when the changes of DNA stem lines and biological characteristics would occur; SHCC is possible to be determined by serum AFP values; and that the survival rate of the patients can be further improved by early finding and treatment of SHCC less than 3 cm in diameter.