Twenty episodes of shunt-associated ventriculitis caused by staphylococci or streptococci were treated with intraventricular vancomycin together with removal of the shunt and insertion of an external drain. Systemic antibiotics given concurrently included intravenous vancomycin or flucloxacillin. All the patients responded to therapy although five had re-infections and one had a relapse. Four patients were treated solely with intrathecal vancomycin. We now use intraventricular vancomycin alone for 'blind' treatment of uncomplicated shunt-associated infections when Gram-positive cocci are seen in the ventricular CSF.