Before 2006, Pompe disease or glycogenosis storage disease type II was an incurable disease whose treatment was merely palliative. The development of a recombinant human alpha-glucosidase enzymatic replacement therapy has become the first specific treatment for this illness. The aim of this guide is to serve as reference for the management of the late-onset Pompe disease, the type of Pompe disease that develops after one year of age. In the guide a group of Spanish experts make specific recommendations about diagnosis, follow-up and treatment of this illness. With regard to diagnosis, the dried blood spots method is essential as the first step for the diagnosis of Pompe disease. The confirmation of the diagnosis of Pompe disease must be made by means of an study of enzymatic activity in isolated lymphocytes or a mutation analysis of the alpha-glucosidase gene. With regard to treatment with enzymatic replacement therapy, the experts say that is effective improving or stabilizating the motor function and the respiratory function and it must be introduced when the first symptoms attributable to Pompe disease appear.