We evaluated auditory function in 50 patients with unilateral acoustic neuroma. By comparing pure tone audiometric thresholds and distortion product otoacoustic emissions, we classified their hearing impairment into three categories: neural hearing loss (group I, n = 7), mixture of neural and cochlear hearing loss (group II, n = 5), and cochlear hearing loss (group III, n = 38). In auditory brainstem response (ABR) examinations, only wave I was present in group I; group II exhibited wave I alone or no waves; and in group III, all waves were present in patients with mild deafness, delayed waves III and V or wave V alone in those with moderate deafness, and no responses in those with profound deafness. Tone decay was observed only in groups I and II, whereas recruitment phenomena were present only in group III. Speech discrimination was poor and out of proportion to the pure tone audiometric configuration in groups I and II, whereas it corresponded well with the degree of hearing loss in group III. These findings indicate that ABR wave I alone, tone decay, and poor speech discrimination are characteristic to neural hearing loss associated with acoustic neuroma. The differences and similarities between auditory neuropathy and acoustic neuroma are discussed.