Previous studies of perilymph proteins have emphasised the difficulty of obtaining samples free of blood or serum proteins. The present investigation has established a method of polyacrylamide gel electrophoresis, which enables contaminated specimens to be readily identified and therefore discarded. Analysis of uncontaminated samples has confirmed the presence of an elevated perilymph protein in cases of acoustic neurinomata. Perilymph proteins have been separated and identified and although no characteristic pattern of proteins associated with acoustic neurinomata has emerged, further work should be undertaken to establish the site of origin of perilymph proteins and the pattern of abnormalities to be expected in pathological processes.