Infections influence pregnancy by gaining access to the pregnant reproductive tract, infecting the placenta, the chorioamnion and the decidualised uterus. The negative impact pathogens can have during gestation is thought to involve innate immune responses aimed at the microbe, leading to excessive inflammation or apoptosis at the materno-fetal interface. Studies on the mechanisms of such actions have focused recently on the innate immune pattern recognition receptors (PRR), specifically, Toll-like receptors (TLRs) and Nod-like receptors (NLRs). These are now thought to play an important, if not a key role in infection-related pregnancy complications. Thus, inappropriate or inadequately controlled TLR and NLR-mediated reactions by the placenta and other gestational tissues may link infection with adverse pregnancy outcome. Understanding the regulation of TLR and NLR expression and function at the maternal-fetal interface in both normal and pathologic pregnancies is, therefore, critical for the development of better predictive and interventional strategies for women at risk of infection-associated adverse pregnancy outcomes. This chapter will review the current knowledge on the involvement of TLRs and NLRs at the maternal-fetal interface, and what the consequences of their function are on pregnancy outcome.