Amniotic fluid embolism (AFE) is a rare pathological syndrome, sometimes fatal that arises as an obstetric complication during vaginal delivery, caesarean, immediate postpartum or during pregnancy. It remains as an important cause of fetal and maternal morbidity and mortality. The authors present a clinical report of a young woman who developed an acute respiratory failure during labour demanding invasive mechanical ventilation and an urgent caesarean. In spite of early medical intensive therapy, hypoxemia was refractory and had a progressive worsening leading to multi-organ failure and ultimately to death. Diagnosis was confirmed through the identification of fetal material in the lumen of maternal pulmonary microcirculation.