Abstract: Sexually mature male mice were exposed to different doses of aluminum chloride in drinking water for twelve weeks. Fertility was significantly reduced in males exposed to aluminum chloride. The number of resorptions and number of females with resorptions were significantly increased in females impregnated by males exposed to aluminum chloride. Ingestion of aluminum chloride significantly reduced testicular and epididymal sperm counts and increase in testosterone and luteinizing hormone (LH) serum levels. Also, absolute weight of the testes, absolute and relative weights of the seminal vesicles and preputial glands were significantly reduced. Furthermore, histological changes were found in testicular sections of adult male mice ingested aluminium chloride. Congested blood vessels, increased amount of interstitial connective tissue and destruction of the seminiferous tubules with large necrotic areas and degenerative cells have been observed. The results indicated that ingestion of aluminum chloride by adult male mice would cause adverse effects on fertility and reproduction.