Lateral surgical approaches to the base of the skull through the temporal bone often result in a large cavity with exposed dura and vascular structures and no possibility of reconstruction of the middle ear conductive hearing mechanism. Subtotal petrosectomy with tympanomastoid obliteration provides a relatively safe and secure closure of the surgical defect in the temporal bone and eliminates the problems associated with an open mastoid cavity. Eradication of all accessible air cell tracts and mucosa in the petrous pyramid, obliteration of the eustachian tubal orifice, closure of the external auditory canal, and fat obliteration of the middle ear and mastoid clefts are essential in the procedure. Over the last 10 years this technique has been utilized in 372 base of skull procedures with a complication rate of less than 5%. Infection occurred only in those cases with draining cavities or contaminated wounds.