**Abstract**

Pesticides include several classes such as insecticides, herbicides, fungicides, and have widespread usage in agriculture. Different type of pesticides and their combinations affect dairy animals through their lifetime and the livestock industry. Under chronic exposure conditions, hormonal and cellular systems of animals, which play a role in reproduction, are affected dramatically. Some of the insecticides act as endocrine disruptors and impair reproductive hormone metabolic pathways via the hypothalamic-pituitary-gonadal (HPG) axis. Additionally, insecticides could have harmful effects on reproductive organs that may cause infertility. The aim of this chapter is review the toxic effects of insecticides on animal reproductive system focusing on molecular mechanisms.

**Keywords:** organophosphates, organochlorines, pyrethroids, male and female reproduction system, endocrine disruption
