Four patients with post-partum hemolytic uremic syndrome were treated with plasma exchange using fresh frozen plasma as replacement. Each patient had microangiopathic hemolysis, thrombocytopenia, and progressive renal and hepatic failure. Disseminated intravascular coagulation was a major feature in each case. The microangiopathy and thrombocytopenia resolved in each patient following plasma exchange. Normalization of renal and hepatic function occurred in three patients, including one patient who died as a result of coronary artery dissection. One patient died as a result of an intracerebral bleed. Plasma exchange with fresh frozen plasma replacement appears to be of benefit if used early in the course of post-partum hemolytic uremic syndrome.