Aim of the work-Methionine is essential for maintaining proper growth and development in mammals. Also, cholesterol enriched diets significantly increase cholesterol level in body tissues. The present study aims to investigate the effects of dietary cholesterol and /or methionine on the histological and some histochemical changes in the testis and epididymis of the male rats. Material and methods- sixty adult male rats (5-7 weeks old) were used in this study and divided into 6 groups. Group 1 served as the control group (C). The following 5 treated groups administered the diets for four months. Group 2 treated with a diet enriched with 2% cholesterol, group 3 received 0.5%  methionine, group 4 received 2%  methionine, group 4 treated with 2%  cholesterol and 0.5%  methionine, group 5 received 2% cholesterol and 2%  methionine.Results- Testes isolated from rats fed excessive amount of cholesterol showed disturbance in spermatogenesis and the epididymal structure with altered total protein, polysaccharides and collagen fibers. Dietary low doses of methionine with or without cholesterol improved spermatogenesis and architecture of the epididymis, but addition of high dose of methionine caused many drastic changes in the testis and the epididymis.Conclusion-Low dose ofmethionine (0.5%) showed ameliorative effect against adverse effects of cholesterol ,but the high dose (2%) showed less protective effect.