Despite recent reports of very low infection rates, cerebral spinal fluid shunt infection remains a persistent and devastating problem in most neurosurgical centers, occurring in 5–10% of procedures. Shunts are most commonly colonized by skin commensal organisms. Staphylococcus epider-midis accounts for 40% of shunt infections; 5. aureus accounts for 20%. Organisms like S. epidermidis produce an extracellular slime, or glycocalyx, which allows them to adhere to shunt material and inhibit the host's defense mechanisms. Formation of a biolayer containing microcolonies of the organism on the prosthesis further inhibits attempts to eradicate the infection. Patients with shunt infections can have a wide variety of clinical symptoms, ranging from wound infection, meningitis, and peritonitis to more indolent symptoms like malaise or simple shunt obstruction. Growth of skin commensals only from shunt equipment cultured in broth media tends to considerably overestimate shunt infection. Removal of all the infected shunt equipment and interval external ventricular drainage produce the highest infection cure rate and lowest mortality rate. Antibiotic treatment alone is very effective for organisms, such as Hemophilus influenzae, that commonly cause meningitis in the general community, but has limited success and a high mortality rate with common shunt-infecting organisms. None of the procedures designed to prevent infection, including meticulous antisepsis and prophylactic antibiotic drugs, has been proven effective by randomized controlled trial. However, recent meta analysis of combined prophylactic antibiotic trials suggests that antibiotic prophylaxis is effective. Future efforts to prevent shunt infection will concentrate on new biomaterials, including those impregnated with antibiotic drugs.