A total of 20 commercial fish and shellfish products consisting of 11 fish species were analyzed before and after broiling on a city gas range for carcinogenic N-nitrosamines by using a nitrosamine specific detection technique (chemiluminescence detection). The mean concentration of N-nitrosodimethylamine (NDMA) in 15 uncooked fish products except dried squids was found to be 2.4μg/kg, and the maximum value found was 9.4μg/kg. The levels of nitrosamines in these products increased remarkably upon broiling, and the average value of NDMA of gas-broiled samples was 6.4μg/kg, and the maximum value found was 26.1μg/kg. The NDMA content of 5 uncooked dried squids ranged from 15.4μg/kg to 84.0μg/kg, with an average value of 46.3μg/kg; in contrast, those in gas-broiled squids ranged from 23.6μg/kg to 313μg/kg, with an average value of 130.2μg/kg. Minute quantities of N-nitrosodiethylamine were detected when “akodai” fillets preserved in “sake” -less were broiled; in addition, N-nitrosopyrrolidine was detected when dried squid samples were broiled on a gas range or even broiled on an electric range. Covering fish products with aluminum foil or broiling them on an electric range was found to be effective in decreasing NDMA formation.