Mutation in genes encoding for proteins involved in glycogen synthesis, degradation or regulation results in various inborn errors of glycogen metabolism. The disorders that result in abnormal storage of glycogen are known as glycogen storage diseases. We report a rare case of an infant who presented with fever, cough, respiratory difficulty and failure to thrive. He was diagnosed with acid maltase deficiency, also known as Pompe's disease, one of the rare types of glycogen storage disease.