We developed a simple method for the separation of rat retinal sublayers. The rat retina was carefully removed from the sclera and treated in trypsin solution. After this treatment, the retinal sublayers could be easily separated by using Millipore filter paper into an outer nuclear layer, an inner nuclear layer, an inner plexiform layer, and a ganglion cell layer + nerve fiber layer. The viable cells of each of the sublayers could be cultured on a poly-L-lysine coated chamber for at least several weeks in Eagle's minimum essential medium supplemented with calf serum and glucose.