BACKGROUND: Transcranial random noise stimulation has previously been used to manage tinnitus. This study assessed the feasibility of adjuvant transcranial random noise stimulation with conventional steroid treatment for idiopathic sudden sensorineural hearing loss with or without tinnitus. METHODS: Prospective, randomized, single-blind study was conducted in Eulji University hospital. Twenty-four patients with idiopathic sudden sensorineural hearing loss were admitted for treatment between March 2019 and February 2020. The study group received 4 sessions of adjuvant transcranial random noise stimulation (frequency band: 0.1-100 Hz; target, T7/T8; duration: 20 minutes), while the control group received only conventional treatment. Hearing levels at admission, discharge day (day 7), and 4 weeks later and clinical characteristics were assessed. The primary outcome measure was hearing improvement at 4 weeks after neuromodulation. The secondary outcome measure was the presence of tinnitus at 4 weeks. RESULTS: The mean hearing thresholds improved significantly over time (P < .05). Although initial hearing levels did not differ between the 2 groups, the study group had a significantly better hearing at 4 weeks after discharge (P > .05). A significant interaction was also observed between the mean hearing thresholds at various timepoints and transcranial random noise stimulation (P=.001). However, the persistence of tinnitus after treatment did not differ irrespective of the allocation groups. CONCLUSION: Adjuvant transcranial random noise stimulation seems to be a potential treatment option for hearing restoration in patients with idiopathic sudden sensorineural hearing loss without serious complications. However, transcranial random noise stimulation does not seem to alleviate tinnitus.