We investigated the prognostic significance of the presence or absence of vertigo and tinnitus, the timing of the initiation of treatment, the type and severity of hearing loss, and age in 72 patients who had experienced sudden hearing loss. We found that the factors associated with a positive prognosis were the absence of vertigo, the presence of tinnitus, initiation of treatment within 7 days, a greater degree of hearing loss in the low frequencies, and a hearing loss of less than 45 dB. Age had no effect on prognosis.