Infantile Pompe disease (glycogen storage disease type 2) is a fatal disease with autosomal recessive inheritance, leading to hypertrophic cardiomyopathy, hypotonia and respiratory failure. It is a progressive condition due to accumulation of glycogen in the muscles. We aimed to present a case of infantile Pompe disease in a patient who had giant QRS complexes in electrocardiographic monitoring and hypertrophic cardiomyopathy involving the interventricular septum and the left ventricle on echocardiography.