A total of 547 patients with idiopathic sudden hearing loss were divided into eight groups according to the days (1-8 days) of their initial visit after onset, and initial hearing thresholds, hearing recovery and its process were investigated. There were no significant differences in initial hearing thresholds and hearing recovery among the eight groups. However, a difference was noticeable in the distribution of the thresholds at the initial visit and that on the 7th day between groups 1, 2 and 7. Many cases showed rapid recovery in groups 1, 2 and 7. We speculate that the treatment influenced the hearing recovery process in patients who showed relatively rapid recovery.