The effects of soy sauce and sugar on the formation of heterocyclic amines (HAs) in marinated pork, eggs, and bean cakes were studied. Food samples were immersed in water in the presence of various levels of soy sauce and sugar, and the mixtures were subjected to simmering at 98+/-2 degrees C for 1 h in a closed saucepan. The various HAs in marinated food samples were analyzed by HPLC with photodiode-array detection. Results showed that seven HAs: 2-amino-3-methylimidazo[4,5-f]quinoline (IQ); 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx); 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ); 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx); 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1); 2-amino-1-methyl-6-phenylimidazo[4,5-f]pyridine (PhIP); and 2-amino-9H-pyrido[2,3,-b]indole (AalphaC) were detected in marinated pork, while five HAs: IQ, MeIQx; 4,8-DiMeIQx; PhIP; and AalphaC in bean cakes, as well as four HAs, MeIQx, 4,8-DiMeIQx, Trp-P-1 and PhIP in eggs. In most samples PhIP was formed in largest amount, followed by MeIQx, 4,8-DiMeIQx, IQ, AalphaC, Trp-P-1 and MeIQ. The amounts of HAs produced in marinated food samples followed an increased order for each increasing level of soy sauce or sugar. Marinated juice was found to contain a higher content of HAs than marinated foods.