Objective: Diabetes mellitus is recognized as one of the serious global health problems. There are evidences regarding the high prevalence of sexual dysfunction in diabetic patients. Experimental studies revealed a positive effect of Vitex agnus-castus (Vitex), on sexual function and behaviors. In this research, the effect of Vitex on sexual hormones in streptozotocin-(STZ) induced diabetic rats was investigated. Materials and methods: A Thirty adult female Wistar rats were divided into five groups. 1-control group (non-diabetic), 2- diabetic group (received normal saline) and three induced diabetic groups treated with different doses (400, 200 and 100 mg/kg) of Vitex. Treatment groups received Vitex fruit extract by gavage for 7 days. The levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone and estrogen in serum were measured. Results: Levels of LH, FSH, estrogen and progesterone and average body weight was lower in diabetic group compared to control group (p <0.010). Animals received high dose of Vitex fruit extract (400mg/kg) had significantly higher levels of serum LH, FSH, estrogen and progesterone compared to diabetic group (p < 0.010). In animals receiving minimum dose (100mg/kg) of Vitex, no difference was observed compared to diabetic group (p > 0.010). Conclusion: It can be concluded that Vitex fruit extract probably has regulatory effect on diabetes-induced change in the levels of sex hormones in female rats. Vitex fruit extract can improve serum levels of sex hormones in an animal model of STZ-induced diabetes.