Chorioamnionitis refers to inflammation of the amniochorionic membrane, and is a significant cause of maternal and neonatal morbidity. Chorioamnionitis most often occurs as a result of ascending infection, and is commonly associated with premature rupture of the membranes. Chorioamnionitis is generally the result of a polymicrobial infection, with Ureaplasma urealyticum, Mycoplasma hominis and Gram-negative anaerobes being frequent causative organisms. The mainstay of treatment includes antimicrobial agents, antipyretics, expedition of delivery and supportive care. Further research is required to identify mechanistic pathways and early biomarkers that accurately predict women at higher risk of adverse maternal and neonatal outcomes, and that can thus lead to the development of additional treatment and prevention strategies. © 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.