The decomposition of carnosine, anserine, and balenine during storage of the big-eye tuna and the sei whale meats was studied with a view to ascertain the formation of methyl derivatives of histamine and β-alanyl-histamine. A chromatographic deteiination of these amines on a 15cm column of a cation exchange resin (JEOL, LCR-2) was achieved using a borate buffer of pH 10.2 having sodium concentration of 0.32N, at 52°C. When the big-eye tuna meats with and without addition of chopped sardine skin were stored at 5°C for 12 days or 20°C for 5 days, and when the sei whale meats with and without addition of mackerel slime at 25°C or 37°C for 3 days, the meats turned putrid in the late stages of the storage periods. The amounts of anserine in the big-eye tuna, and carnosine and balenine in the sei whale did not decrease. Although a lot of histidine was decarboxylated into hislamine in the big-eye tuna meat at 20°C, the methyl derivatives of histamine and β-alanyl-histamine were not detected.