Only a few cases of temporal choroidal fissure cyst are reported. We describe a new case of an 8 years old girl who manifested complex partial seizure. The diagnosis was made by magnetic resonance imagining (MRI). The signal intensity of the cyst was identical to the cerebrospinal fluid (CSF), and the underlying hippocampus was compressed by the cyst. The seizures were medically controlled. The value of MRI in the diagnosis and medical treatment will be discussed.