The goal of this study was to investigate the mechanisms, diagnosis, and treatment of shunt dependency syndrome in patients with temporal lobe arachnoid cysts who were initially treated with cystoperitoneal (CP) shunting. Thirteen patients with temporal lobe arachnoid cysts who had initially been treated with CP shunt placement and had developed shunt dependency syndrome were treated by the senior author at Tiantan Hospital between April 2010 and January 2012. The clinical manifestations, neuroimaging findings, intracranial pressure (ICP) data, treatment methods, and therapeutic results were reviewed retrospectively. The study included ten males and three females. The mean age at the time of development of shunt dependency syndrome was 12.3 years (range 5.5-24 years). In most patients, neuroimaging findings showed a collapsed cyst (the cyst appeared almost unchanged in only one patient) and normal or small ventricles (only one patient had enlarged ventricles). Three patients underwent simple replacement of the shunt, four underwent ventriculoperitoneal shunt placement, and the other six underwent lumboperitoneal shunt placement. All patients experienced resolution of their symptoms postoperatively. The mean duration of follow-up was 20 months. Shunt dependency syndrome is a rare but serious complication of shunting an arachnoid cyst. This condition is similar to the slit ventricle syndrome, but also has some differences. ICP monitoring may confirm the diagnosis when there are no significant radiological findings. Achievement of a shunt-free state might be the ultimate goal for all shunted patients.