Apneic patients have hypotonia of the lingual and supra-hyoid muscles. The dysfunction of theses muscles leading to a collapse of the upper airway is responsible for the apnea. The goal of this study, designed as a before-after trial, is to determine the effect of lingual and supra-hyoid muscle strengthening on obstructive sleep apnea. Thirty-four patients with obstructive sleep apnea were included (consecutive sample). Only 16 patients completed the study. The treatment consisted of 30 sessions of transcutaneous neuromuscular stimulation administered to the submental region associated with muscular exercises. The effect on apneic events was analyzed with a polysomnography before and after the treatment. Thirteen patients could be analyzed for the statistical studies. The mean apnea-hypopnea index (AHI) decreased from 32.9 to 20.6 (Wilcoxon rank test: P = 0.017). Seven patients ended the study with an AHI of less than 10, and three more patients decreased their AHI by more than 50%. This treatment significantly decreased the AHI in most of the patients. A larger study with more patients and with a long-term follow-up is necessary to determine the place of physiotherapy in the treatment of obstructive sleep apnea.