The clinical and computerised tomographic findings in 40 patients with primary pontine haemorrhage were reviewed. Twenty-nine patients were hypertensive. Four patients had angiographic or necropsy evidence of vascular malformations. In 33 cases, there was rapid deterioration to maximal neurological deficit; whereas in seven cases, there was sudden onset but subsequent progression to maximal deficit 24 hours to 5 days following the initial ictus. Seven patients had clinical features considered atypical for pontine haemorrhage. Five patients survived and four of these were capable of performing activities of daily living within 3 months of the haemorrhage. In all cases CT showed a hyperdense non-enhancing brain stem haematoma. There was evidence of ventricular extension in 27 cases. There was CT evidence of subarachnoid blood in only two patients who also had vascular malformations. In 26 cases, there was CT evidence that the haematoma extended to the midbrain and in four cases to the thalamic region. In six cases CT was repeated 6 to 21 days after the initial scan and it showed resolution of the haematoma in size and density; none of the haematomas showed post-contrast enhancement on initial or follow-up CT.