The fact that embryos can be obtained in vitro undermines the role of the oviduct. However, it has been demonstrated that when in vitro produced bovine zygotes are cultured in the oviduct of sheep, cattle or mice the embryo quality is improved compared to the embryos produced in vitro. Thus the oviduct is not simply a passive organ required only for transporting the embryo to the uterus but also provides a suitable microenvironment for the early embryo. The study of physiological mechanisms and interactions between the embryo and the oviductal environment is essential to understand the correct processes of early embryo developmental. This knowledge can be used to improve current in vitro procedures providing high quality embryos capable of continued development and implantation, and resulting in viable births.