Interaural intensity relations producing equal loudness when pure tones were presented alternately, and median plane localization when they were presented simultaneously, were studied in normals, mon-aurally masked normals, and patients with unilateral sensorineural hearing loss, both with and without loudness recruitment. The 2 types of judgment do not yield equivalent results. With important qualifications, median plane localization requires more nearly equivalent SPLs at the 2 ears than does equal loudness. Loudness recruitment must always be measured by alternate stimulation of the 2 ears.