In an autopsy series of 430 spontaneous intracerebral haematomas 44 cases, or 10.2 percent, were caused by a proved neoplasm, including 21 anaplastic gliomas, 17 metastases, 2 oligodendrogliomas, 2 malignant lymphomas, and one meningioma. These instances of massive bleeding into brain tumour represented 2.4 percent of about 1,800 primary and secondary cerebral neoplasms proved by necropsy. In only four of the patients with primary brain tumours (two glioblastomas, one oligodendroglioma invading the leptomeninges, and one primary malignant lymphoma), three of them with a history of arterial hypertension, were the presenting symptoms these of a spontaneous intracerebral haemorrhage, and the tumour itself was not diagnosed until surgery or necropsy. One patient with acute haemorrhage into a glioblastoma of the basal ganglia showed a rapidly lethal course, while the others demonstrated one or more episodes before the onset of the acute fatal illness and a prolonged period from the time of the bleed until death. The clinical features and the pathogenesis of spontaneous haemorrhage into cerebral neoplasms are briefly reviewed.