We studied the efficacy and pharmacokinetics of intraventricularly administered vancomycin in three patients with shunt-associated staphylococcal ventriculitis. We instilled 10 mg of the drug intraventricularly every 24 hours. Cerebrospinal fluid (CSF) levels were measured 1 hour after instillation and then every 2 hours. Peak vancomycin levels reached a mean of 292.9 microg/mL. The mean trough levels, measured immediately before readministration of vancomycin, were 7.6 microg/mL; this level has proved to be sufficient for maintaining the necessary steady-state serum concentration of vancomycin. All three patients were cured clinically and bacteriologically, and CSF parameters returned to normal within 5-13 days. No side effects were observed. Our results suggest that intraventricularly administered vancomycin is a valuable therapeutic strategy for treating shunt-associated staphylococcal ventriculitis. In addition, we provide evidence that 10 mg of vancomycin, administered intraventricularly every 24 hours, allows maintenance of therapeutic drug levels in the CSF for at least 24 hours.