Brain myosin V is a member of a class of unconventional myosins. Using antibodies against brain myosin V, its distribution in the rat retina has been examined. It was detected in the inner and outer plexiform layers, in the somas of cells forming the inner nuclear layer, and in the ganglion cell layers. Faint labeling was also detected in the inner segments of the photoreceptor cells. In semithin retinal sections and isolated rod photoreceptor cells, a bright punctate labeling pattern was observed in the outer plexiform layer, corresponding to the rod photoreceptor synapses. The results found suggest that a major role of myosin V in the outer retina is in these synapses.