Six hundred and fifty four fish samples containing mainly of twenty five kinds of important edible fishes and 144 fish samples of yellowfin tuna, swordfish and black shark were analyzed for gross β and gross α. Upon a wide survey on radioactive contamination of these fishes, it was obvious that all kinds of fishes caught by Taiwan fishing fleet were about 1 pci/g (most of them less than 1 pci/g) which is much lower than the maximum permissible level of activity in marine material adopted by Windscale, U. K. In this survey, no significant difference is found in the different fishing areas and the radioactive content is regardless of fish body size. Therefore, the fishes from these areas could be considered safe in respect to radioactive contamination.