Trigeminal neuralgia (TN) is a common pain in the orofacial region. Dandy-Walker syndrome (DWS) is a congenital malformation of the cerebellar and the fourth ventricle foramina atresia. Dandy-Walker syndrome is rarely found in patients with TN. This article presents a 36-year-old man with the symptoms of typical TN. His physical examination was entirely normal. An enhanced magnetic resonance imaging was taken. Magnetic resonance imaging revealed the bilateral lateral ventricle, the fourth and third ventricle significantly enlarged with severe obstructive hydrocephalus, a huge posterior fossa cyst connected with the fourth ventricle, and hypoplastic vermis. The pain was controlled by Tegretol. The reported case suggests that DWS is an unusual cause of TN.