Due to myelin and axonal insults in multiple sclerosis individuals, motor coordination problems and endocrine imbalance may develop. This study aims to evaluate the role of chronic demyelination on the hypothalamic-pituitary-gonadal axis in the mouse model of multiple sclerosis. 20 adult C57/BL6 male mice were divided into 2 groups (n = 10/each) as follows: the control group (CONT) received a regular diet for 17 wk; and the experimental group (cuprizone [CPZ]) was fed with 0.2% CPZ for 12 wk and, then CPZ was withdrawn for 5 wk. Serum testosterone, histopathology of the brain and testis, and sperm analysis were evaluated. The hypothalamic myelin content was significantly decreased in the arcuate nucleus following the 12 wk of CPZ consumption compared to the CONT group, and the statistical difference remained until 17 wk. Testosterone levels declined significantly in the CPZ group compared to the CONT group in the 12 and 17 wk. A significant decrease was observed in the height of the seminiferous epithelium and the interstitial tissue area, and the number of seminiferous epithelial cells in the CPZ group compared to the CONT group in the 12 and 17 wk. The sperm count, motility, and viability in the CPZ group significantly decreased compared to the CONT group in the 12 and 17 wk of the study. Chronic demyelination induced by CPZ intoxication, maybe through damage to the hypothalamus arcuate nucleus, leads to the hypothalamic-pituitary-gonadal axis disturbance and damage to the testis and spermatogenesis subsequently.