Most cases of sudden sensorineural hearing loss (SHL) are idiopathic. Consequently, the otologist may be asked to predict hearing recovery and select a treatment strategy without fully understanding the disease process. We retrospectively reviewed the charts of 837 patients with SHL to evaluate the prognostic value of specific clinical parameters and the effectiveness of steroid and vasodilator treatments. Treatment response was defined by the patient's subjective response and audiological criteria. Patients who were treated with steroids and/or vasodilators were more likely to improve. Patients who improved had a worse initial pure-tone average (PTA) than those who did not improve. In addition, those with poorer initial speech discrimination scores, worse initial thresholds at 4,000 Hz, younger age, and greater number of treatments were more likely to improve. Neither the electronystagmogram results nor the initial audiogram shape were valuable indicators. Recognition of prognostic indicators can help in counselling patients and in the evaluation of treatment response.