Rat is one of the most commonly used model animals for biological research. The organs and systems of human being are somewhat similar to that of rat in structure as well as functions, making it a valuable choice for research experimentation in biological sciences. A number of studies have been conducted to evaluate the potential risks and toxicity of different elements on the physiology and histology of rats. There is need to address certain environmental factors affecting rats condition during experimentation. Reproduction along with its pathologies is under investigation on larger scale throughout the world, being central for the existence of a species. These studies focus on the major factors that influence reproductive function. Review of literature clearly indicated the unwanted consequences of over nutrition, malnutrition, high or low temperature, non-enriched housing, improper handling, intense or poor light exposure and environmental pollution on histology and hormonal profile of reproductive system of rats.