From the histochemical observations of enzymes in carbohydrate metabolism in tumor cells using rat ascites hepatomas containing free cells, it was revealed that there are some differences in metabolic pattern between ascites hepatoma AH 13 and AH 39. AH 13 cells apparently had an usual anerobic glycolytic pathway showing the intense histochemical reactions for glucosephosphate isomerase, aldolase and lactate dehydrogenase, being accompanied by glycogen metabolism with predominant glycogenesis showing a histochemical reaction for UDPG-glycogen glucosyltransferase and with less predominant glycogenolysis showing the considerably intense reaction for phosphorylase. Phosphoglucomutase was also histochemically demonstrated intensely in AH 13 cells. Thereby, glycogen deposits appeared moderately in tumor cell bodies in AH 13. On the other hand, AH 39 cells had more predominantly the same anerobic pathway, but they were not accompanied by the same glycogen metabolism. Poor glycogenesis and moderately weak reaction for phosphorylase were demonstrated in the cells. Phosphoglucomutase was weakly demonstrated. Thereby, no glycogen was deposited in the cell bodies, with exception of the later stage after the inoculation. In the long-term cultivation of these two strains, the enzymatic properties of tumor cells were changeable in carbohydrate metabolism. Increase of glycogen storage occurred in AH 13 tumor cells being accompanied by an increase of the phosphoglucomutase activity and decreases of both the glucosephosphate isomerase and aldolase activities. It was due furthermore to the somewhat reduction of the phosphorylase activity. Slight increase of glycogen storage in AH 39 cells also occurred in the cell bodies, in spite of increasing phosphorylase activity. The glycogenesis presumably was intensified by the cultivation. It was also related to the reduction of the glucosephosphate isomerase activities.