An electrophotographic photoreceptor is formed by a photosensitive layer containing a naphtylhydrazone compound of the formula: ##STR1## wherein X and Y are independently a hydrogen atom, lower alkyl group, lower alkoxy group, phenoxy group or arylalkoxy group; R.sup.1 is a naphtyl group; R.sup.2 is a hydrogen atom, lower alkyl group, allyl group, substituted or unsubstituted phenyl group, or aralkyl group; and l and m are 1 or 2. The photoreceptor thus formed is not only highly sensitive but resistant to ozone deterioration, which markedly improves the durability thereof.