A nucleotide-stimulated protease of rat retina was partially purified by DEAE-cellulose column chromatography. A 50-fold increase of an ATP-stimulated protease activity over a cytosol fraction was achieved by this chromatography. Maximum stimulation of protease activity by ATP was achieved at 2 mM. The pH optimum of the ATP-stimulated protease activity was between 7.5 and 8.5. 2 mM GTP stimulated the protease activity by 91%. 5 mM cyclic AMP stimulated the protease activity by 73% while 5 mM cyclic GMP stimulated the activity by 84%. The possible role of the nucleotide-stimulated protease in retina and potential involvement of the protease with inherited retinal dystrophy are discussed.