Tract infections, stomach acne, gonorrhea and claymidia was investigated on the body weight and semen quality of testes of adult male wistar rats. Twenty- four (24) adult male Wistar rats were separated into four groups each containing 6 wistar rats (n=6). Group A served as the control group while groups B, C, and D served as the experimental groups. Group received distilled water, while group B, C, and D received respectively 10.7, 21.4 and 28.6mg/kg/bw/day of tetracycline orally for 21 days. The rats were sacrificed on the 22nd day and their testes were harvested and fixed in Bouin's fluid for light microscopy. The body weights of the treated rats did not increase significantly (P>0.05) compared with the controls. The sperm quality decreased significantly (P<0.05) in a dose-dependent manner in the treated rats compared with the controls. Conclusion: This study concluded that tetracycline has adverse effect on the sperm parameters of the testes in wistar rats.