The foveal avascular zone was measured angiographically in 144 subjects with diabetic retinopathy and 27 control subjects. Statistical significance was defined as P < 0.01. Quantitatively, the foveal avascular zone was significantly smaller in control eyes (median = 0.405 mm2) than in eyes with diabetic retinopathy, and smaller in eyes with background diabetic retinopathy (BDR; median = 0.737 mm2) than in eyes with proliferative diabetic retinopathy (PDR; median = 0.866 mm2) and preproliferative diabetic retinopathy (PPDR; median = 1.001 mm2). Qualitatively, the contour of the foveal avascular zone in diabetic retinopathy was irregular (29.2% of eyes with diabetic retinopathy vs 3.7% of control eyes) with scattered round microaneurysms. Diabetic retinopathy is characterized by an irregular, large foveal avascular zone with scattered microaneurysms.