Following ejaculation into the vagina, dog sperm remain functionally competent for many days, acquire the ability to fertilize, and are delivered to an appropriate site within the uterine tube synchronously with the appearance of fertile oocytes. The mechanisms involved in regulating this system are complex, and allow for sperm storage within the female reproductive tract. The aim of this paper is to review current knowledge of the transportation of sperm and their biology within the reproductive tract of the bitch.