Benzene has been considered as an occupational hematotoxin and leukemogen. The present study was conducted to determine the effects of oral administration of benzene on reproductive organs and testicular spermatogenesis in rats. Adult rats were divided into three weight matched groups (Gr. I-III) containing 6 each. Gr. I rats received vehicle only and served as control. Rats in Gr. II and III were fed orally with 0.5 and 1 ml kg(-1) dose of benzene for 14 and 9 days, respectively and autopsy was done on 15th and 10th day. Food and water intake and gross behavioral changes were recorded daily during the entire treatment. Results showed no significant change in reproductive organ weights viz. testis, epididymis and ventral prostate in benzene-treated (0.5 or 1 ml kg(-1)) rats than that in controls. But, caused a significant decrease (p < 0.005) in weights of seminal vesicles in rats treated with both 0.5 and 1 ml kg(-1) doses compared to control. In contrast, at higher dose (1 ml kg(-1)) of benzene, significant (p < 0.001) decline in body weight and 100% mortality was observed on day 10 of autopsy. In treated rats, testicular cytotoxicity was marked by multinucleated giant cells formation, cytoplasmic vacuolization, pyknosis of nuclei, chromatolysis, desquamation and dissolution of germ cells in tubular lumen. The quantitative analysis of spermatogenesis showed a significant (p < 0.001) decrease in number ofA-spermatogonia (in 1 ml kg(-1) dose only), primary spermatocytes (non-pachytene and pachytene) and spermatids (round and elongated) in treated as compared to control rats. The diameters of testicular tubules and Leydig cells nuclei were also significantly (p < 0.001) reduced in treated rats. A steady loss in food and water intake recorded and signs of ill health were observed in treated (0.5 or 1 ml kg(-1)) rats. Results of the study indicated antitesticular lantispermatogenic effects of benzene at 0.5 and 1 ml kg(-1) dose in rats.