Knowledge of the composition of vaginal microbial ecosystem is essential for understanding the etiology, prevention and treatment of vaginal diseases. A baboon model has been used to provide detailed understanding of reproductive physiology and immunology applicable to women. However little is known about the composition of its vaginal microbial ecosystem. In this book, the findings of a study on baboon vaginal microbial flora at different stages of the menstrual cycle (menstrual, follicular, luteal) using cultivation method are discussed. The bacterial species isolated included Lactobicillus species, the predominant bacteria present in the vagina of healthy women.