Chorioamnionitis is a puerperal infection that exists in histologic, clinical, and subclinical forms. This entity is believed to play a causative role in many cases of spontaneous preterm delivery. It also is associated with an increased risk of dysfunctional labor. This article focuses on the effects of chorioamnionitis on the progress of labor and the appropriate treatment of patients with clinical chorioamnionitis. The epidemiology, pathogenesis, and associated maternal and neonatal outcomes also are reviewed.