This study was done to evaluate reproductive potential of male mice following early exposure to dimethoate. Thirty-six Swiss albino male mice were divided into three groups of twelve mice each: first group injected intraperitoneally with distilled water, and used as a control group, while second and third groups injected with dimethoate at doses of 0.1 and 0.2 ml dimethoate/100 ml distilled water, respectively for 7 days. At the end of experiment, the mice were weighed and then were killed. Testis and epididymis weights were recorded, sperm parameters were evaluated.