Carcinogenicities of mutagenic heterocyclic amines in cooked foods have been tested in CDF1 mice and F344 rats of both sexes. Eight heterocyclic amines--Trp-P-1, Trp-P-2, Glu-P-1, Glu-P-2, MeA alpha C, A alpha C, IQ, and MeIQ--were given to mice and/or rats at 0.02 to 0.08% in the diet continuously. In mice, all heterocyclic amines tested were demonstrated to be carcinogenic. Hepatocellular carcinomas were induced in a high incidence in all groups treated with heterocyclic amines. Hemangioendothelial sarcomas were also induced by Glu-P-1, Glu-P-2, MeA alpha C, and A alpha C. Most hemangioendothelial sarcomas were located in the interscapular brown adipose tissue. In mice given IQ, forestomach and lung tumors were also observed in a high incidence. Carcinogenicity tests on MeIQ are ongoing, and interim data by week 83 show that MeIQ also induces forestomach tumors in addition to liver tumors. In rats, hepatocellular carcinomas were induced by Trp-P-1, Glu-P-1, Glu-P-2, and IQ. In rats given Glu-P-1, Glu-P-2, and IQ, adenocarcinomas in the small and large intestines, squamous cell carcinomas in the Zymbal gland and clitoral gland were also observed in a high incidence.