**Abstract**

This chapter examines the impact of diabetes mellitus type 2 (DM 2) on the vitality of male reproductive cells collected from Zucker diabetic fatty (ZDF) rats which could be a suitable experimental model for simulating this metabolic disorder. Epididymal spermatozoa were subjected to the assessment of motility, membrane integrity, mitochondrial activity, DNA fragmentation, and oxidative profile. Our results show that DM 2 in combination with obesity negatively affects the sperm vitality and increases the chances of oxidative damage to male gametes. In conclusion we may state that DM 2 has a negative impact on the spermatogenic aspect of male fertility and decreases the sperm quality.

**Keywords:** diabetes mellitus type 2, obesity, ZDF rats, male reproduction, spermatozoa
