Introduction: A diagnosis of chorioamnionitis is based on clinical criteria which only manage 60% sensitivity and have little usefulness in predicting fetal compromise. Ultrasound emerges as a useful diagnostic alternative. An impact might be made on perinatal morbimortality by improving diagnosis through the search for echographic markers of fetal infection, thereby enabling early intervention in pregnant women at risk of fetal compromise, especially regarding subclinical chorioamnionitis. This review was aimed at providing evidence supporting an association between ultrasound's echographic findings and the presence of chorioamnionitis in in utero (congenital) fetal infection. Materials and methods: A review of the existing literature was made in medline, ovid, ebsco, ProQuest, lilacs and scielo databases from January 1985 to October 2012. Original research and review articles were included. Results: Cervical length shortening, the presence of sludge, oligohydramnios and thymus involution are the markers which have been shown to have the greatest association with intra-amniotic infection. Conclusions: Ultrasound is a tool to be considered when diagnosing in utero maternal and fetal infection.