Serum copper, ceruloplasmin, and urinary copper were estimated in 13 normal subjects and 24 patients with primary retinitis pigmentosa. The serum copper levels in patients appeared to be higher and ceruloplasmin levels lower than in the normal subjects. The patients seem to fall into 2 categories with regard to urinary copper. About a third of them excreted 2-4 times more copper in the urine, while in the others the excretion is comparable to normal subjects. It appears possible that there exists in India a genetic isolate of retinitis pigmentosa with altered copper metabolism. The distribution of these patients may be different between the northern and southern parts of the country.