Lafora-like bodies in an 8-year-old cat were studied light and electron microscopically and histochemically. In addition ot Lafora-like bodies composed of branching filaments, glycogen granules and electron-dense materaisl, abnormal accumulations of glycogen granules attracted attention. The most remarkable features were the developmental processes of the branching filaments originating directly from glycogen granules. Lafora-like bodies in the present study showed ultrastructural, histochemical, and enzymatic similarities to those described in the previous reports in Lafora's disease, glycogenosm is considered to be probably related to the productive mechanism of Lafora-like bodies.