Di-ethylhexyl phthalate (DEHP) –a common type of phthalate plasticizers- has become a major environmental toxic hazard to human health especially the reproductive system. This work aimed to assess the subchronic toxic effects of DEHP on adult albino rats' reproductive organs (ovary and testis) using body & reproductive organs weight parameter, combined with biochemical, histopathological and immunohistochemical methods. Forty adult male & female albino rats were divided as follows: male control groups (10 rats = “5 negative & 5 positive”); female control groups (10 rats= “5 negative & 5 positive”); male DEHP-treated group (10 rats) and female DEHP-treated group (10 rats), both were given DEHP dissolved in corn oil at a dose of 3gm/kg once daily for 4 weeks. The results of present study revealed the followings: a decrease in body weight and reproductive organs' weights (ovary and testis); hormonal disruption effects (decrease estrogen “estradiol” & testosterone serum levels in females & males respectively); histopathological and immunohistochemical changes in ovary and testis in DEHP-treated groups as compared to control groups. In conclusion, oral exposure of adult albino rats to DEHP at a dose of 3 g/kg daily for 4 weeks resulted in toxic hazards to male & female reproductive organs (ovary and testis).