Objects of the present invention are to provide a novel anhydrous crystalline .beta.-maltose, its preparation and uses. The present invention attains the above objects by providing an anhydrous crystalline .beta.-maltose with a melting point of 154 to 159.degree. C.; a process for producing the same, comprising a step of keeping hydrous crystalline .beta.-maltose in an organic solvent at an ambient temperature or higher for the dehydration; and uses of the same.