Pompe disease (glycogen-storage disease type II) is an autosomal recessive disorder caused by a deficiency of lysosomal acid α-glucosidase (GAA), leading to the accumulation of glycogen in the lysosomes primarily in muscle cells. In the adult form of the disease, proximal muscle weakness is noted and muscle volume is decreased. The infantile form is usually fatal. In the adult form of the disease the prognosis is relatively good. Muscle weakness may, however, interfere with normal daily activities, and respiratory insufficiency may be associated with obstructive sleep apnea. Death usually results from respiratory failure. Effective specific treatment is not available. Enzyme replacement therapy with recombinant human GAA (rh-GAA) still remains a research area. We report the case of a 24-year-old student admitted to the Department of Pulmonary Diseases because of severe respiratory insufficiency. Clinical symptoms such as dyspnea, muscular weakness and increased daytime sleepiness had been progressing for 2 years. Clinical examination and increased blood levels of CK suggested muscle pathology. Histopathological analysis of muscle biopsy, performed under electron microscope, confirmed the presence of vacuoles containing glycogen. Specific enzymatic activity of α-glucosidase was analyzed confirming Pompe disease. The only effective method to treat respiratory insufficiency was bi-level positive pressure ventilation. Respiratory rehabilitation was instituted and is still being continued by the patient at home. A high-protein, low-sugar diet was proposed for the patient. Because of poliglobulia, low molecular weight heparin was prescribed. The patient is eligible for experimental replacement therapy with rh-GAA.