The bacterial population of the primate vaginal canal is an infant primate's first exposure to the microbial population inhabiting the outside world. Yet, little is known about this population and the effect it might have on the development and survival of the infant primate. As a first step toward characterizing the vaginal microbiota of a nonhuman primate, we used denaturing gradient gel electrophoresis to evaluate variations in the vaginal microbiota of a group of 35 baboons (Papio hamadryas), which were housed in a facility where they shared the same diet and the same environmental conditions. We found that, despite the uniform environment, there were appreciable differences in the composition of the microbiota from one individual to another. Our results also indicate that a simple swab test is sufficient for sampling the vaginal microbiota in the field, a finding that should help make more detailed characterization of the microbiota of wild primates feasible in the future. Am. J. Primatol. 72:467–474, 2010. © 2010 Wiley-Liss, Inc.