The following key and descriptive notes have been prepared in an endeavor to lessen the difficulties involved in the identification of the various species of Ptinid beetles that occur, usually as pests of stored products, in dwellings and warehouses in Canada. For a number of years, Mr. H. E. Gray of the Division of Entomology has been collecting these beetles from flour sheds and other types of warehouses throughout Canada. Most of the material on which the key is based was supplied by Mr. Gray, and much of the data on the distribution of several of the species is a result of Mr. Gray's observations.