Naturally occurring drusen in two eyes of a rhesus monkey resolved after the application to the retina of mild laser coagulation. Clinically, resolution took place approximately nine days following treatment. The cellular mechanism for resolution was observed by light and electron microscopy over a time period of three days to six weeks after treatment. A previously unidentified phagocytic cell, probably derived from the pericyte of the choriocapillaris, was observed to remove drusenoid material after laser photocoagulation. The cell appeared to be analogous to the mesangial cell of the renal glomerulus.