With the widespread therapeuticand emerging prophylactic use of TAM, there has been much discussion about side-effects of the drug, particularly its organ toxicity. The present study was designed to evaluate the toxic effects of tamoxifen (TAM) on the liver and kidney of experimental rats and the possible protective effects of an aqueous methanolic extract of cumin (Cuminum cyminum L), which is rich in phenolics and flavonoids against tamoxifen toxicity. Thirty two female adult rats were used in the study and divided into four groups. The first group was designed as controls. The second group was intraperitoneally injected with TAM (10 mg/kg body weight) daily for 10consecutive days. The third group was intraperitoneally pre-injected with cumin extract (10 mg/kg) daily for 20 consecutive days, starting 10 days before the TAM-injection. The fourth group was intraperitoneally injected with cumin extract (10 mg/kg) daily for 20 consecutive days. The level of lipid peroxidation of serum as well as the histology of liver and kidney of the rats can be adversely affected by TAM-treatment. Cumin administration decreased the levels of lipid peroxidation and normalized the histological structure of the studied organs. In conclusion, the administration of cuminprior to tamoxifen resulted in amelioration of the toxicity to the organs fromtamoxifen.