Objective: This study aimed to create a multiple regression model for predicting hearing outcomes of idiopathic suddensensorineural hearing loss (ISSNHL). Methods: The participants were 205 consecutive patients (205 ears) with ISSNHL (hearing level 40 dB, interval between onset and treatment 30 days). They received systemic steroid administration combined with intratympanic steroid injection. Data were examined by simple and multiple regression analyses. Three hearing indices (percentage hearing improvement, hearing gain, and posttreatment hearing level [HLpost]) and 7 prognostic factors (age, days from onset to treatment, initial hearing level, initial hearing level at low frequencies, initial hearing level at high frequencies, presence of vertigo, and contralateral hearing level) were included in the multiple regression analysis as dependent and explanatory variables, respectively. Results: In the simple regression analysis, the percentage [tearing improvement, hearing gain, and HLpost, showed significant correlation with 2, 5, and 6 of the 7 prognostic factors, respectively. The multiple correlation coefficients were 0.396, 0.503, and 0.714 for the percentage hearing improvement, hearing gain, and HLpost, respectively. Predicted values of HLpost calculated by the multiple regression equation were reliable with 70% probability with a 40-dB-width prediction interval. Conclusion: Prediction of HLpost by the multiple regression model may be useful to estimate the hearing prognosis of post ISSNHL.