Careful presurgical otologic assessment of the contralateral ear in acoustic tumor patients is essential, not only to establish baseline data but more importantly to resolve the intense patient anxiety that arises almost immediately when the diagnosis is presented. Any subsequent reduction in hearing acuity in the contralateral ear after the tumor ear has been deafened, poses serious psychological, socio-economic and medical problems. Three detailed case reports of sudden hearing loss in the contralateral ear of postoperative acoustic tumor patients are presented. The lesion sites include: the middle ear, cochlear, and retrocochlear. In each case, hearing returned to its previous or near-previous levels. Allergic factors were implicated in two cases.