This chapter reviews the types of shunt complications, their likelihood, and some clinical examples. Cerebrospinal fluid (CSF) shunting and particularly ventriculoperitoneal shunting is a common procedure used to treat a variety of CSF flow dynamic pathologies including obstructive, communicating, and normal pressure hydrocephalus (NPH) from a variety of etiologies. There are several types of specific long-term complications associated with shunting procedures in addition to those more likely seen in the NPH population in particular. These include underdrainage of CSF, overdrainage of CSF, mechanical failures of the hardware such as alterations in valve resistance over time, malposition of the tubing, and frank breakage, CSF leak, subdural hemorrhage or hygroma, seizure, and infection. Underdrainage conditions arise when shunt systems develop increased resistance across the valve over time, disconnection or kinking of the system components, or migration of the tubing out of an appropriate position for proper drainage and/or reabsorption.