Background: Quercetin is a strong antioxidant and long-term treatment of STZ-diabetic animals and it has been shown to reduce oxidative stress.

Objective: antioxidants have essential effect on spermatogenesis and sperm parameters. Enhanced oxidative stress and changes in antioxidant capacity are considered to play an important role in the pathogenesis of chronic diabetes mellitus.

Methods: Wistar male rat (n=40) were allocated into three groups, control group (n=10) and Quercetin (QR) group that received 15mg/kg (IP) QR, (n=10), and Diabetic group that received 55 mg/kg (IP) streptozotocin (STZ) (n=20) which was subdivided to two groups of 10 STZ group and treatment group. Treatment group received 55 mg/kg (IP) STZ plus15mg/kg QR, daily for,4 weeks, respectively however, the control group just received an equal volume of distilled water daily (IP). Diabetes was induced by a single intra peritonea injection of streptozotocin (55 mg/kg). Animals were kept in standard condition. In 28day after inducing diabetic 5cc blood were collected for testosterone, TAC, MDA and Ox-LDL levels and testes tissues of Rat in whole groups were removed and sperm was collected from epididymis then prepared for analysis.

Results: Sperm population, percentage of sperm viability and motility significantly increased in group that has received 15 mg/kg (IP) Quercetin (p<0.05) in comparison to control and experimental groups.