Drug administration via an intraventricular reservoir is useful in the treatment of leukemic and carcinomatous meningitis that occurs in patients who have previously received lumbar intrathecal chemotherapy. The intraventricular route, however, is associated with a higher incidence of infectious complications compared with therapy given by the lumbar route. To characterize the infectious complications associated with such reservoirs, we reviewed the 10-year experience of the Pediatric Branch, National Cancer Institute, National Institutes of Health, and Children's Orthopedic Hospital, Seattle, WA, with 61 patients (49 with leukemia, 8 with lymphoma, 4 with solid tumors) who had intraventricular reservoirs placed for administration of chemotherapy. The reservoirs were in place for a median of 36 weeks and were punctured a median of 29.5 times. Infectious complications occurred in 14 of 61 patients (23%) and Propionibacterium acnes was the most common organism recovered from cultures. Twelve patients (19.7%) had 19 episodes of clinically suspected and microbiologically documented meningitis or of positive intraventricular reservoir cerebrospinal fluid cultures without symptoms which were treated successfully. Local cellulitis occurred at the site of intraventricular reservoir placement in 2 patients (3.3%) and removal of the intraventricular reservoir was necessary for successful management. Nine patients had their intraventricular reservoir removed (5 because of associated infection and 4 because of malfunction unassociated with infection). Four asymptomatic patients had positive cerebrospinal fluid culture for P. acnes. Two of these patients subsequently developed clinical meningitis with the same organism (P. acnes) found at the time of the initial asymptomatic episode. While asymptomatic patients with positive cerebrospinal fluid cultures may not require immediate therapy, they should be followed carefully for the development of meningitis. Thus although the risk of infection is not insignificant, the morbidity associated with these infections does not preclude use of the intraventricular reservoir in patients who might benefit from them.