This study retrospectively and prospectively analyzes uncomplicated, noninfected, primary ventriculoperitoneal shunting procedures and ventriculoperitoneal shunt revisions in children done at the University of Wisconsin Hospital from July 1973 to December 1979. We compared the infection rates between patients whose procedures were done without prophylactic antibiotics and those who received prophylactic single dose methicillin at the time of operation. Among 105 procedures done without prophylactic methicillin, there were 8 infections: 4 occurred after 73 primary shunt placements and 4 followed 32 shunt revisions. Among 66 procedures done with prophylactic methicillin. there were 3 infections; all followed primary shunt insertions. There was no infection after 32 shunt revisions in which prophylactic antibiotics were used.