**Abstract**

In most research involving female reproductive function, female animals particularly mice and rats are usually employed. This may perhaps be due to their well-defined reproductive cycle (estrous cycle) as well as the ability to breed and handle them easily. The short and precise length of estrus cycle usually 4–5 days make mice models the choicest mammal when it comes to human related research. Also, they possess very short reproductive age typically 7–8 months reaching sexual maturity at weeks 4–7 following their birth. Although many similarities exist between this model and humans, however, there also exist obvious distinctions between the human female reproductive system and that of mice. Humans have average length of their reproductive or menstrual cycle of about 28–29 days with their reproductive ages between 10–40 years. These relevant differences between mice and human reproductive system constitute the limitations to the use of this models. Therefore, the scope of this chapter will be to explore the basic knowledge of laboratory mice by examining their reproductive system anatomy and physiology, the fertilization process, estrous cycle and genetic make-up. We hope that this will provide many insights to the use of animal models in female reproductive research.

**Keywords:** female mice, estrogen and progesterone signaling, female reproductive cycle, estrous cycle, ovary
