We present the unusual association between chronic subdural haematoma (CSDH), intracranial arachnoid cyst and autosomal dominant polycystic kidney disease (ADPKD) in a 27-year-old man. CSDH is a documented complication of intracranial arachnoid cyst, the incidence of which is increased in patients with ADPKD. Awareness of this association may lead to earlier diagnosis of ADPKD and treatment of ...