Thrombotic thrombocytopenic purpura (TTP) is a rare and potentially lethal syndrome characterized by severe thrombocytopenia, microangiopathic haemolytic anaemia, and aspecific neurologic symptoms. This syndrome is the result of an abnormal intravascular platelet aggregation which induces transient ischemia in various organs, especially in the central nervous system. Platelet aggregation causes also fragmentation of erythrocytes, thus leading to the characteristic anaemia. The exact cause of TTP is unknown, but a large body of evidence suggest that this syndrome might be due to acquired (immunological) or congenital ADAMTS13 deficiency. The dysregulation of ADAMTS 13 activity could promote massive release of high molecular weight multimers of von Willebrand factor (VWF) from endothelium and, as a consequence, could cause intravascular platelet aggregation. Pregnancy is commonly associated with numerous metabolic, immunological, and haemostatic changes which could increase thrombotic risk: during pregnancy, in fact, it is generally observed an increase of procoagulant activity and a decrease of fibrinolytic activity; moreover, at the end of pregnancy, it is not rare to find thrombocytopenia. All these reasons lead us to consider pregnancy itself as a triggering event for the onset of TTP. The authors describe a case of TTP occurred during puerperium, in a patient who underwent caesarean section.