Objective: The purpose of this study was to determine, through a randomized, double-blind, placebo-controlled trial, whether intratympanic steroid injections (ITSIs) could improve hearing recovery in patients with sudden sensorineural hearing loss (SSHL) who did not respond to initial systemic steroid therapy., Study Design: This was a prospective, randomized, double-blind, placebo-controlled study., Setting: The study was conducted in 2 tertiary referral centers., Patients: A total of 60 patients with idiopathic SSHL who did not respond to an initial round of systemic steroid therapy were included in this study. The subjects were randomized into an ITSI group and an intratympanic normal saline injection (ITNI) group, which were matched by age and sex. A total of 55 subjects completed the study., Intervention: Participants received either ITSIs or ITNIs. Both groups received 4 injections within a 2-week period., Main Outcome Measures: Pure-tone thresholds were compared between the 2 groups 1 month after injection therapy., Results: In the ITNI group, the pure-tone threshold was 69.9 ± 18.5 dB before intratympanic injection therapy. After therapy, the hearing threshold improved by an average of 4.5 ± 6.5 dB, and 10.7% of subjects improved by 10 dB or more. In the ITSI group, the pure-tone threshold was 64.6 ± 17.7 dB before intratympanic injection therapy. After the therapy, the hearing threshold improved by an average of 9.8 ± 8.5 dB, and 44.4% of subjects improved by 10 dB or more. Both the response rate and the level of hearing improvement were significantly greater in the ITSI group than in the ITNI group., Conclusion: These results demonstrate that ITSIs are beneficial as a salvage therapy for the treatment of patients with idiopathic SSHL who fail to respond to initial systemic steroid therapy.