Distribution coefficients of fission products in nitric acid for strongly acidic cation exchanger of sulfonic acid type with different cross-linking and structure were measured by a column method. Uptake of cationic fission products increases with resin cross-linking and decreases of nitric acid concentration. The distribution coefficient of the ion, [KdMn+]*, in a given system is expressed as log [KdMn+]*=B·log[KdMn+]+A where [KdMn+] is the distribution coefficient of the ion at 1M nitric acid for 10% crosslinked gel type cation exchanger, while A and B constants. Deviation from the above relation were observed for Y3+ and complex ions of ruthenium upward for macroporous type cation exchanger and downward for highly porous type cation exchanger. Upward deviation of Y3+ for 10% cross-linked gel type cation exchanger increased with concentration of nitric acid. Consequently, elution sequence varied from Y3+−Eu3+−Pm3+−Ce3++ at 1M nitric acid to Eu3+−Pm3+−Y3+−Ce3+ for the same cation exchanger at 2M nitric acid. The same elution sequence, Eu3+−Pm3+−Y3+−Ce3+, was observed for 8% cross-linked gel type cation exchanger and 10% cross-linking macroporous type cation exchanger at 1M nitric acid.