Spontaneous cerebrospinal fluid (CSF) otorrhea frequently occurs without temporal bone trauma, fracture, surgery, or any identifiable causes. It is usually associated with tegmen tympani defects of the temporal bone in adults. The congenital origin theory and the arachnoid granulation theory have been accepted to explain the tegmen tympani defect. Magnetic resonance imaging (MRI) and computed tomography (CT) are used to show the defects, brain tissue, and the meninges. We recently encountered three cases of spontaneous CSF otorrhea with a defect on the tegmental plate of the temporal bone. High-resolution CT (HRCT) scan of the temporal bones showed the tegmen tympani defects. The defects were successfully repaired with temporal muscle fascia or fascia lata graft and fibrin glue using the middle cranial fossa approach via craniotomy.