Wistar male rats were tested for nephrotoxicity and carcinogenicity after administration of ferric nitrilotriacetate [(NTA) CAS: 139-13-9] (Fe-NTA) [No. of rats (n) = 24] and Al-NTA (n = 24). The control rats were given AlCl3 (n = 10), NTA (n = 10), and saline (n = 10). Sublethal doses of Fe-NTA [5-7 mg Fe/kg (body wt)] and Al-NTA [1.5-2.0 mg Al/kg (body wt)] were chosen and injected ip for 3 months. AlCl3 and NTA were given in equivalent doses and saline was given in equivalent volumes. All the rats given Fe-NTA or Al-NTA had a depressed weight gain, polyuria, and glucosuria from the 1st week. Histologically, acute tubular necrosis and regenerating epithelial cells were observed. Regenerative atypical epithelial cells in the renal cortex were seen at the termination of Fe-NTA or Al-NTA administration. Control rats had no remarkable changes. After 1 year, primary renal cell carcinoma and metastases to liver, lung, and peritoneum were observed only in Fe-NTA-treated rats (14 of 18 surviving rats). On the contrary, there were no tumors in Al-NTA-treated rats (none of 12 surviving rats). The results suggest that nephrotoxicity and renal cell carcinoma are two independent phenomena from Al-NTA treatment and that a long-term sublethal dose of Al-NTA is not related to renal carcinogenicity.