The cases of 67 patients consecutively operated on for acoustic tumors are reported. Preoperative records consist of tumor size and the position of the fourth ventricle on computerized tomography (CT) scans. An analysis is made of the immediate postoperative and current function of the facial nerves. There is a statistically significant relationship between the number of weak or paralyzed seventh nerves and displacement of the fourth ventricle (P less than .05). It is now possible to accurately measure acoustic tumors on preoperative CT scans. The position of the fourth ventricle can also be clearly seen. The current standard of diagnosis and management of acoustic tumors should include a cursor measurement of tumor size on CT scan and a notation of the position of the fourth ventricle. Adoption of this method of reporting will permit meaningful evaluation of treatment for acoustic tumors. This analysis illustrates the importance of accurate measurements in reporting and evaluating surgical results.