Idiopathic sudden sensorineural hearing loss(SNHL) is defined as a sensorineural hearing loss which develops over a period of hours or few days without a definitive causes. The etiology, prognosis, and treatment of SNHL are uncertain. We reviewed records of 76 patients to investigate the efficacy of the stellate ganglion block(SGB)in SNHL. The control group(40 patients) was managed with the medication such as hypaque, heparin, steroid, nicotinic acid, and vitamine. The SGB group(27 patients) was managed with the same medication and SGB (1~2 times/day). The efficacy of treatment was evaluated by mean dB of 500, 1000, 2000 Hz on follow up pure tone audiogram. Recovery rate above 15dB was not different between SGB and the control group (52.4 v.s. 52.0%), though SGB group has much poor prognostic factors. Recovery rate was higher in a case that was treated early. Especially, the recovery rate was 100% when SGB begins within 2 weeks from the onset. Headache and profound type of audiogram were poor prognostic factors. In conclusion, SGB within 2 weeks from the onset is recommanded to improve the recovery rate.