Hexamethylene diamine (1,6-diaminohexane, CAS No. 124-09-4) was administered in the diet to groups of 52 rats (26 males and 26 females) at doses of 50, 150, and 500 mg/kg/day for two generations. A control group received the basal laboratory diet. The F0 and F1 generations were each mated once to produce F1 and F2 generations. Treatment related changes included reduction in weight in F0 males and F1 males and females and reduced food consumption among F0 and F1 males and females in the high dose group. The high dose group also showed reduced litter size, and decreased pup weight on lactation days 14 and 21 for both generations. No other treatment effects were noted with regard to lactation, female body weights, fertility indices, copulatory interval, gestation length, pup survival or appearance, or testes weight or appearance. The authors conclude that the 150 mg/kg/day level can be considered the dietary 'no effect' level. This EPA status report only includes a summary of this study.