The cranial anatomy of the Early Permian synapsid Varanosaurus is restudied on the basis of preYiously described specimens from Texas, most importantly the holotype of the type species V. aCUlirostris. and a recently discovered, excellently preserved specimen from Oklahoma. Cladistic analysis of the Eupelycosauria, using a data matrix 0(95 characters, provides the following hYPOthesis of relationships of VaraIJosaurus: I) VaraIJosaurus is a member of the family Ophiacodontidae; 2) of the ophiacodonlid genera included in the analysis, Varanosaurus and OpniacodOIJ share a more recent common ancestor than either does with the more primitive Arcna('()tnyris; and 3) a clade containing the progressively more derived taxa Edaphosauridae, Haplodus. and Sphenacodontoidea (Sphena. codontidae plus Therapsida), together with Varanopseidae and Caseasauria, are progressively more distant outgroups or sister taxa to Ophiacodontidae. A revised diagnosis is given for VaralJosQurus.