A case of a clinically occult ovarian carcinoma leading to subacute cor pulmonale in a 62-year-old woman is described. The patient was admitted to hospital with increasing respiratory distress. Physical examination and echocardiography showed signs of pulmonary hypertension. She died from circulatory failure. Autopsy revealed a bilateral ovarian carcinoma with diffuse carcinosis of the peritoneum. No gross evidence of pulmonary embolism was present, but microscopic investigation revealed tumour-related microangiopathic lesions causing the lethal pulmonary hypertension.