Use of the subcutaneous ventricular reservoir in the treatment of posthemorrhagic hydrocephalus was studied in a series of 38 patients. All of the patients were considered to be medically labile. Additionally, all had failed conservative modes of therapy consisting of lumbar punctures with or without furosemide or acetazolamide. Management of the hydrocephalus consisted of reservoir placement. Subsequently, taps were performed at various intervals and amounts, depending upon the degree of ventricular dilatation as determined by sonography and signs of increased intracranial pressure. The majority of reservoirs were left in place for 1-2 months. There were no reservoir infections. Once the patients were medically stable, the reservoir was removed and a shunt placed. Eight patients died before shunt placement and 2 patients died after shunting, reflecting a 29% mortality. In no case was a death related to the shunt, but rather reflected the medical lability of the patient population. Four patients (15% of surviving patients) did not require shunting. The total shunt infection rate was 6.9% (among survivors with a shunt in place, 7.7%). These results support the use of the reservoir as an easy and effective means of protecting the cortical mantle while decreasing morbidity related to future shunt placement.