Three cases of acute adrenal haemorrhage complicating heparin induced thrombocytopaenia are described. The patients were 2 men and 1 woman, respectively 62, 74 and 76-year old. They all had orthopaedic problems requiring a treatment by subcutaneous calcium heparinate. Thrombocytopaenia occurred 7 to 10 days after the beginning of treatment, with a progressive return to normal of platelet count on stopping heparin. A syndrome suggestive of adrenal failure appeared on the 10 th to 12 th day consisting of abdominal pain, hyperpyrexia, arterial hypotension, asthenia, altered consciousness. Adrenal hormone levels were decreased. Abdominal scanography demonstrated adrenal haemorrhage in 2 patients. The third patient died before further investigations could be carried out. Hormonal replacement therapy brought things back to normal. Six other similar cases have already been published. The heparin induced thrombocytopaenia probably explains the two paradoxes of adrenal haemorrhage complicating heparin therapy: its occurrence in the absence of excessive anticoagulation, and adrenal venous thrombosis. The presence of abdominal pain, fever, collapse, or hyponatraemia with heparin induced thrombocytopaenia should suggest a possible adrenal haemorrhage. Adrenal CT scans should be carried out rapidly, so that hormone treatment can be initiated without delay.