The ocular fundi of 1,151 apparently healthy colony-born cynomolgus monkeys (Macaca fascicularis) ranging in age from newborn to 19 years were examined using an ophthalmoscope. Two hundred and thirty-eight abnormal findings were recorded in 219 of the 1,151 monkeys. Of these, 23 were related to the optic disc and 115 to the retinal vessels. Of the remaining 100 abnormal findings, 91 were retinal degenerations and 9 were retinal hemorrhages. The 23 optic disc abnormalities consisted of 3 cases of micropapilla, 4 of ectasia and 16 of myelination of the retinal nerve fibers. Of the 115 retinal vascular abnormalities, 87 were arterial tortuosity, one was venous tortuosity, 2 were tortuosity of both artery and vein, 2 were artery-vein crossing, 20 were copper-wire artery, one was inosculation of the artery, one was vascularization of the vein and one was persistent hyaloid artery. Of the 91 retinal degenerations, one was degeneration of the periphery of the macular and the optic disc, 8 were macular degeneration and 82 were peripheral degeneration. Nine cases of retinal hemorrhages appeared under 6 years of age.