The timing and progression of normal term labour is linked with an inflammation-like response in the gestational tissues. However, the upstream signals events which initiate term labour are poorly understood. Toll-like receptor 4 (TLR4) is a receptor for endogenous damage-associated molecular patterns (DAMPs) released from the fetus and/or gestational tissues in late gestation. In this study we investigated the physiological role for TLR4 in normal term delivery, and underlying mechanisms involved. To investigate this, either Tlr4-/- females or wildtype controls were mated to males of the same genotype. In Tlr4-/- mice parturition was delayed by ~13 hours and postnatal mortality was increased, compared to wild-type controls. Inflammatory cytokines and uterine activation genes were quantified using RT- PCR in the gestational tissues in late gestation. In Tlr4-/- females delayed labour was accompanied by a lower expression of Il1b, Il6, Il12b and Tnf mRNA in the placenta, fetal membrane and fetal head. A transient delay in uterine activation genes including Ptgfr, Oxtr and Gja1 mRNA was observed in the uterine and decidual tissues of Tlr4-/- females, when compared to wild-type mice. The leukocyte populations in gestational tissues were also quantified using flow cytometry. In late gestation Tlr4-/- females had a decrease in placental and fetal membrane macrophages as well as the placental neutrophils. Tlr4-/- females also showed a decline in myometrial neutrophils and dendritic cells while displaying an increase of Treg cells in the myometrium. Administration of a TLR4 antagonist to wild-type mice in late gestation could also delay parturition. Collectively these results suggest that activation of TLR4 in late gestation leads to coordination of pro-inflammatory cytokine upregulation, leukocyte recruitment into the fetal and maternal tissues and induction of uterine activation genes, leading to on-time parturition.