The maternal recognition of pregnancy is a physiological process in which the em- bryo announces his presence in the maternal reproductive tract by molecular signs interferon tau (IFN-t) secretion. Luteolitic mechanism trigger by the prostaglandin F2α (PGF2α) on the corpus luteum (CL) blockage, and lifespan and CL-progesterone production prolongation preg- nancy. The events that influence this phenomenum imply the interaction of different structurs as ovary, uterus and embryo. Although the IFN-t is considered to be the basic signal to the maternal recognition of the pregnancy, it is important to keep in mind the role that estrogens, progesterone, and prostaglandin have in the processes of molecular pathways signalling that happen during the implantation window. Key word: Maternal recognition of pregnancy - Bovine embryo - IFN-t.