Bacterial colonization of cerebrospinal fluid shunts is a cause of significant morbidity, causing not only shunt malfunction and chronic ill-health but has also been implicated in an immune-complex glomerulonephritis. Almost all shunt colonizations involve Staphylococcus albus which gains access to the shunt during surgery and grows in microcolonies inside the shunt. The most reliable means of diagnosis at present is serological surveillance. Medical management is usually ineffective in eradicating colonization and colonized shunts must be replaced. Recent work on the impregnation of Silastic with antimicrobial substances to prevent colonization has provided encouraging results.