Objectives: Multiple System Atrophy (MSA) is atypical parkinsonian syndrome (APS) affecting respiration, phonation, resonance, and articulation, which is characterized by a mixed type of dysarthria involving hypokinetic, ataxic and spastic. However, there are still very limited speech interventions for MSA, and these demonstrate contrasting effects. The purpose of this study was to investigate the efficacy of water resistance therapy (WRT) of dysarthria in patients with multiple system atrophy. Methods: A total of 9 patients with MSA-C (cerebellar type) (5 males and 4 females) underwent WRT once per week for 6 weeks. Aerodynamic, acoustic, and auditory-perceptual evaluation were performed before and after voice therapy to determine the efficacy of WRT. In addition, outcomes were compared based on disease duration (less than 4 years and more than 4 years), before and after therapy. Results: Significant improvement in aerodynamic, acoustic, and auditory-perceptual evaluation was found following WRT. After therapy, in aerodynamic analysis, increased VC, MPT and reduced Psub were observed. Significant improvements were also observed for CPP, L/H ratio and reduced Jitt, PPQ, sPPQ, vF0, Shim, APQ, sAPQ, vAm, STD, NHR, σCPP, and σL/H ratio. In addition, in auditory-perceptual analysis, harsh voice, strained-strangled voice, pitch fluctuations, vocal tremor, prolonged phonemes, and speech intelligibility were improved. Moreover, significantly reduced sAPQ, vAm & σCPP were seen in the less than 4-year group, while significant improvement in APQ was observed in the more than 4-year group. Conclusion: Accordingly, significantly positive effects were found in respiration, phonation, and articulation changes following WRT for patients with MSA. WRT may be useful speech therapy for improving dysarthria in patients with MSA.