The objective of this study was to assess, in a controlled experimental system, whether the concentrations of polyamines (Pa) in urine or erythrocytes increase during the process of colon carcinogenesis in rats, and whether such changes reflect tumor volume. Colon carcinoma was induced in Sprague-Dawley rats by subcutaneous injection of 1, -2 dimethylhydrazine (DMH). 24-hour urine and blood samples were collected and analysed for their Pa concent, with highpressure liquid chromatographic method. The levels of any Pa derivatives in either urine or erythrocytes at 32 weeks after the administration of DMH were not significantly high compared with the control group at the same week. However, certain increases of Pa in erythrocytes were observed in the levels of putrescine (1.3 times), spermidine (1.3 times), and spermine (1.5 times) respectively compared with the control group and there were high positive correlations between tumor volume and the levels of each Pa derivatives. On the ground of the results, Pa in erythrocytes seems to be the sensitive parameter for tumor volume compared with Pa in urine.