Epidermoid cysts are tumors familiar to neurosurgeons, but intramedullary epidermoid cysts are rare. The authors report the case of a 6-year-old girl presenting with progressive paraparesis. A midthoracic intramedullary mass was revealed on myelography and magnetic resonance (MR) imaging and confirmed as an intramedullary epidermoid cyst at surgery, at which time the cyst was removed. This is the fourth report documenting a purely intramedullary epidermoid cyst occurring in a child. The pathology and etiology, epidemiology, clinical features, radiology (including MR image characteristics), and surgical treatment of such rare intramedullary benign tumors are discussed. Magnetic resonance imaging reduces the delay in diagnosis of spinal cord tumors but should be guided by clinical judgment.