Background: It is still a challenge to find an effective treatment for tinnitus. The aim of this study was the evaluation of carbamazepine and oxcarbazepine effects on tinnitus.Methods:In a randomized double-blind clinical trial, 57 patients who were visited in a university hospital due to chronic non-pulsatile tinnitus, were randomized in three groups and treated with carbamazepine (300-600 mg/day), oxcarbazepine (450-900 mg/day) and placebo for 12 weeks. Visual analogue scale (VAS) and tinnitus severity index (TSI) were measured in all subjects in the beginning and at the end of the 8(th) and 12(th) weeks of the trial. Data was analyzed by repeated measure analysis, paired and independent t-test.Results: Among 51 participants who completed the trial course (28 men, 23 women), carbamazepine, oxcarbazepine and placebo decreased tinnitus severity in 56.6%, 46.2% and 38.5% of patients according to VAS, and in 61.1%, 58.8% and 50% of patients according to TSI, respectively. The effects of carbamazepine and oxcarbazepine were better in the first 8 weeks of treatment. However, their effect on tinnitus did not show any statistical difference in comparison with placebo (P = 0.34, P = 0.28).Conclusion: Carbamazepine and oxcarbazepine are not more effective than placebo in decreasing tinnitus severity.