A case of amniotic fluid embolus is described with an acute onset occurring 90 min after surgical delivery in a mildly pre-eclamptic primigravida undergoing Caesarean section for a breech presentation. Severe disseminated intravascular coagulation and massive postpartum haemorrhage were corrected and she went on to make a full recovery. The pathophysiology of amniotic fluid embolism is discussed and new diagnostic tests are reviewed. It is suggested that in this patient an amniotic fluid collection in dilated uterine veins was mobilised as venous tone returned following the offset of spinal anaesthesia and sympathetic blockade.