Marine fishes, sardine(Sardinops melanosticta), scad kingfish(Caranx equula), horse mackerel(Trachurus japonicus) and file fish(Navodon modestus), were stored for fifty days with partial freezing at$-3.5^{circ}C$. During the storage, the changes in microflora and volatile nitrogen content was investigated. The fishes exhibited $10^4;to;10^6$ of bacterial cells per square centimeter of their skin just before they were submitted to the storage. The bacterial cell number was increased as $10^6;to;10^8$ cells as the storage time passed over twenty-two days. Offensive odor which is typical in the spoilage of fishes became strong as increase the bacterial cell numbe. The major isolates among the three hundred strains of bacteria isolated from the fish skins were identified as Pseudomonas I/II, III/IV-H, Vibrio and Moraxella. The same was found in the spoiled fishes, however, Pseudomonas I/II, was predominant on contrast to that of fresh fishes. Pseudomonas III/IV-NH, Flavobacterium, Cytophaga and Micrococcus were also found in early period of storage, but they disappeared as the progress of storage. Nine per cent of isolates were unidentified.