Phagocytosis of rod outer segments and of latex beads was demonstrated in retinal pigment epithelium explants from adult albino rats. Uptake of latex particles increased steadily over a 24 hr period while ingestion of rod outer segments peaked after 2 hr of incubation, then decreased. Postnatal changes in phagocytic capabilities of retinal epithelium were examined in 10- to 35-day-old rats. Retinal epithelium from 10–15 day neonatal animals ingested lastex particles but few rod outer segments. The number of outer segment packets ingested increased with increasing age of the explant donor. The results suggest that the mechanisms involved in phagocytosis of nonspecific particles (latex beads) appear earlier in development than the mechanisms necessary for phagocytosis of photoreceptor outer segments.