This research was undertaken to observe the harmful effect of androgenic anabolic steroids over the male reproductive system. A total of 120 animals were used. The animals were administered injection of androgenic anabolic steroid for short and long periods intramuscularly once a week. The animals were divided in the following groups (A) control / untreated males, (B) treated for short period i.e. acute group, (C) treated for long duration i.e. chronic group, and (D) group left untreated for another 14 weeks to see the withdrawl effects of the drug. The blood was drawn by cardiac puncture, for the estimation of serum concentration of reproductive hormones in male rats, including testosterone, LH, and FSH. Animals were sacrificed and testis were removed for the histological study and scanning electron microscopy, and were analysed statistically. Hormonal analysis revealed significantly decreased level (p<0.001) of FSH, LH and testosterone in acute and chronically treated groups, while the level of these hormones returning towards normal in the withdrawl group. The histological sections of the testis revealed that there is a time related effects over the spermatogenesis, resulting in the decrease in the relative weight of the testis, count and the number of seminiferous tubules along with the decrease in the number and the diameter of the interstitial cell nuclei in the treated animals. These results are further confirmed by performing scanning electron microscopy.2 While looking the effects in the group which has been withdrawn from the drug for another 14 weeks period shown that the animals in this group shown to return of all the parameters back to or near to normal. From these finding it can be said that the androgenic anabolic steroids has dose and time related effects over the male reproductive tissue i.e. the testis. But these effects can be reduced if the drug is withdrawn after confiming that they are produced after the therapy is started. From these findings it can be concluded that androgenic anabolic steroids has toxic effects on the germ cells depending on the time period. However, if the drug is withdrawn than the effects can be reduced. This aspect of the study needs to be further evaluated.