The aim of this study was to investigate the effect of high-dose betahistine treatment added to vestibular rehabilitation (VR) on the disability, balance and postural stability in patients with unilateral vestibular disorder. The VR group (group 1, n = 24) and the VR + betahistine group (group 2, n = 23) were analyzed retrospectively. All patients were evaluated before and after an 8-week customized VR in terms of disability (Dizziness Handicap Inventory, DHI), dynamic balance [Dynamic Gait Index (DGI)] and postural stability (static posturography). In group 1 and group 2, differences between DHI, DGI and falling index score on static posturography before and after the exercise program were significant (p < 0.05). In addition, a significant difference was detected only in group 2 in the variables evaluated in static posturography-Fourier 4 analysis (p < 0.05). Both VR and betahistine + VR have a positive effect on disability and balance in patients with unilateral vestibular disorder. Betahistine treatment added to VR was effective in increasing postural stability.