Postoperative infections are major complications of cerebrospinal fluid (CSF) shunting in the treatment of hydrocephalus and other conditions with obstructed CSF circulation. In a retrospective study 884 first-time shunted patients with hydrocephalus operated on in the years 1958-1989 were investigated with special reference to the infection rate and to the influence of the following variables: time period, age of the patient, education of the neurosurgeon, length and time of the operation and the exact placement of the distal drain. The overall infection rate for all implanted CSF shunts was 7.4% (5.7-9.3%) and the acute rate of infection was 6.2% (4.6-7.9%). The rate of infection was virtually constant for all variables with the exception of the education of the neurosurgeon. Neurosurgical trainees particularly had a significantly higher rate of infection. Shunt infection is still a major complication. The infection rate has not declined in recent decades. It is not possible to relate any main cause to the infection rate. The literature recommends removal of the infected shunt combined with antibiotics. The use of prophylactic antibiotics is still controversial. No prospective, double-blind studies, including a sufficiently large number of patients to evaluate this issue, exist today.