The novelty described in this case report is the simultaneous development of arterial and venous thrombosis in a previously healthy Caucasian 37-year-old male with newly diagnosed warm autoimmune haemolytic anaemia (WA-AIHA). Clinical presentation included sensorimotor dysphasia, right arm paresis, abdominal pain, and swelling of the left leg. Computed tomography angiography showed partial occlusion of the left middle cerebral artery and multiple infarcts of the kidneys and spleen, while Doppler ultrasound revealed thrombosis of the left popliteal vein. A therapeutic dose of low-molecular-weight-heparin was instituted together with rituximab, leading to the complete serological and haematological remission. The exact thrombotic risk factors in WA-AIHA are still not completely identified and no generally accepted guidelines on thromboprophylaxis exist. The severe onset of the WA-AIHA might point towards a close association between haemolysis itself and thrombosis, raising the question of the necessity of prophylactic anticoagulation.