Objectives: Mutational falsetto (MF) is a functional voice disorder involving failure to transition from the high-pitched voice of childhood to the lower-pitched voice of adolescence and adulthood. The low mandible maneuver (LMM) is used by professional singers to relax the larynx and expand the resonance space. It relaxes suprahyoid muscles and pushes the larynx backwards, so it can be used as a therapy for MF. Material and Methods: The data of 20 MF patients treated by the LMM were analyzed in this study. All of the patients were asked to complete the Voice Handicap Index-10 (VHI-10) before the first session, and again 2 weeks after the second visit. The Grade-Roughness-Breathiness-Asthenia-Strain (GRBAS) scale scores and fundamental frequency (F0) were analyzed for each patient. Results: All except 1 patient reported that they completed the exercises without difficulty; the patient who did not perform the exercises cited reasons other than their difficulty. Only 2 patients failed to transition from MF to a lower-pitched voice. The GRBAS scale scores (all parameters) differed significantly between the first and second sessions. The VHI-10 score also changed, i.e., self-perceived voice quality was improved significantly, as was the F0. Conclusions: Our results showed that the LMM is an efficient and rapid technique for treating MF patients and shows high patient compliance.