One hundred neurological patients were subjected to "A" and "B" scanning. In 43 histologically verified intracranial masses were demonstrated. For the midline echo determination, the accuracy was 94.2% in cases without displacement and 90.4% in cases with proved midline displacements. The sound-picture tracings of the 43 verified intracranial tumors are analyzed. The accuracy of the method is still low; however, it is simple, easily reproducible, and quite inexpensive. It may find great importance as a screening test for more elaborate neuroradiologic examination in cases with clinical suspicion of mass lesions.