Fifty-six patients, treated with a series of anesthetizing blocks of the stellate ganglion for idiopathic sudden sensorineural loss, were compared with 20 patients of similar diagnosis who were treated by other means as to amount of pure-tone gain, speech discrimination improvement, nature of symptoms, and delay in start of surgery. Seventy percent of the stellate-ganglion-block-treated patients achieved substantial hearing improvement. Only 15% to 20% of the non-stellate-ganglion-block-treated patients achieved substantial hearing improvement in discrimination or pure-tone levels. The delay time from onset of symptoms to start of stellate block therapy appears to be important. The type of tinnitus, presence or absence of vertigo, and fullness in the ear may be useful prognostic signs.