In order to eliminate the possible differences among the specimens measured under different conditions, viz., fresh, frozen and thawed, a series of experiments on the effect of freezing on the morphometric characteristics of skipjack tuna were carried out. Measurements on the fork length (F.L.) and six other morphometric characters, i.e., head length (H.L.), snout to the insertion of the pectoral fin (S.P.), snout to the insertion of the first dorsal fin (S.Ⅰ.), snout to the insertion of the second dorsal fin (S.Ⅱ.), snout to the insertion of the ventral fin (S.Ⅴ.) and snout to the insertion of the anal fin (S.A.), were made under the three different conditions. The results of statistical tests reveal that (1) the character S.Ⅱ.shows the greatest differnce caused by the effect of freezing and the character S.Ⅴ. shows the smallest; (2) there is no significant difference among the three different conditions for individual character; and (3) in case of morphometric study, therefore, consideration on the effect of freezing could be neglegible.