A 28-year-old female with a twin pregnancy at 29 6/7 weeks who was having premature uterine contractions developed acute respiratory failure due to sudden pulmonary oedema requiring mechanical ventilation. No evidence for venous thromboembolism, pulmonary infection or myocardial infarction was found. Subsequently a mild coagulopathy and foetal distress developed. Ultrasonography revealed oligohydramnios of one of the foetuses. A Caesarean section was performed and postoperatively mother and babies had an uneventful clinical course. By exclusion of other causes, we diagnosed severe maternal acute respiratory distress due to the amniotic fluid embolism syndrome in a twin pregnancy.