2,6-toluenediamine is used as an intermediate in the production of dyes for furs and textiles, and of flexible polyurethane foams and elastomers. a bioassay of 2,6-toluenediamine dihydrochloride for possible carcinogenicity was conducted by feeding diets containing the test chemical to f344 rats and b6c3f1 mice. groups of 50 rats of each sex were fed the test chemical at 250 or 500 ppm, for 103 weeks groups of 50 mice of each sex were fed the test chemical at two doses, 50 or 100 ppm, for 103 weeks. groups of 50 untreated rats and 50 untreated mice of each sex were used as matched controls. in male rats, islet-cell adenomas of the pancreas and neoplastic nodules or carcinomas of the liver occurred in non-significant dose-related trends. the occurrences of tumors in dosed female rats were not significantly different from those in control rats. significant results in the negative direction were observed in the incidences of c-cell tumors of the thyroid in male rats and of fibroadenomas of the mammary gland in female rats. in low dose male mice, lymphomas occurred but were not statistically significant, and the occurrence of hepatocellular carcinomas in female mice was dose related but not statistically significant. it was concluded that, under conditions of the bioassay, 2,6-toluenediamine dihydrochloride was not carcinogenic for male and female f344 rats or for male and female b6c3f1 mice