A simple, rapid, specific and reproducible assay for tissue glycogen is described. The method involves the incubation of a denatured tissue homogenate with amyloglucosidase resulting in the complete hydrolysis of glycogen to glucose. The glucose content of the homogenate supernatant is then determined with the aid of a glucose analyzer. The method has been used to measure the glycogen content of a variety of discrete and complex animal tissues and is particularly convenient for microdeterminations.