A series of 16 patients with chronic or subacute subdural hematomas treated with continuous external drainage of the subdural space is reviewed. Of these only 44% went on to require subdural-peritoneal shunt placement. There were no complications in treatment and no clinical or laboratory evidence of infection in any case. The outcome, measured by neurological examination, was not different between the shunted and nonshunted groups. In conclusion, continuous external drainage of the subdural space in chronic and subacute hematomas of infancy frequently is an effective, definitive treatment. This approach should be considered as the initial procedure prior to subdural-peritoneal shunting. © 1991 S. Karger AG, Basel.