Background: The increase in the level of oxidative stress and the decrease in the level of Myoinositol in type 2 diabetes, af- fect sperm parameters. We investigated the effect of the Myo- inositol, as an antioxidant, on sperm parameters in diabetic rats. Materials and Methods: 18 adult male rats were divided in three groups: control, diabetic (streptozotocin (65 mg/kg b.w) and nicotinamide (110 mg/kg.b.w), intraperitoneal injection) and diabetic + Myoinositol group (300 mg/kg.b.w/day, gavage, 8 weeks). After 8 weeks, semen samples were collected from the epididymis, and after preparing the smear, Eosin-Nigrosin, Diff quick staining was used for the sperm viability and mor- phology, respectively. Data were analyzed using ONE WAY ANOVA and Tuky's test, and the significance level was P<0.05. Results: A significant decrease in sperm count, viability, pro- gressive motility, total motility, normal sperm morphology (P<0.001), as well as a significant increase in stationary mo- tility, number of headless sperms and tailless sperms was ob- served in the diabetic group compared to the control (P<0.001). In The diabetic + Myoinositol group, a significant increase in sperm count (P<0.001), viability and progressive motility (P<0.05), total motility (P<0.01), normal sperm morphology (P<0.001) and also a significant decrease in the stationary mo- tility (P<0.01), number of headless sperms (P<0.05), and tail- less sperms (P<0.001) were observed. Conclusion: Myoinositol protects the sperm against type 2 dia- betes by improving sperm count, viability, motility, and mor- phology.