During eligibility screening for the Diabetes Control and Complications Trial, we compared stereoscopic color fundus photography and stereoscopic fluorescein angiography in the detection of diabetic retinopathy in 320 patients (mean age, 24 years [SD, eight years]) with insulin-dependent diabetes (mean duration, 7.0 years [SD, 4.0 years]) and no or mild diabetic retinopathy. Of 153 patients classified as having no retinopathy according to color photographs of seven standard 30 degrees fields of both eyes, 21% of the patients had evidence of retinopathy (mostly one or two microaneurysms in one eye) on review of fluorescein angiograms, including two standard 30 degrees fields in each eye. Of those patients with no retinopathy detected on angiograms, 19% had retinopathy on review of color photographs. When used in conjunction with color photography, angiography allows a modest increase in sensitivity to the earliest signs of retinopathy, a gain potentially useful in some research applications, although not of demonstrated value in patient management.