• This study examined the relationship between the proportion of peripheral retinal nonperfusion and electroretinogram measures in one untreated eye of 44 patients with sickle cell retinopathy. The proportion of peripheral retinal nonperfusion was derived from fluorescein angiographic frames covering 180° of the temporal periphery. The extent of peripheral retinal capillary nonperfusion was greater in patients with peripheral retinal neovascularization compared with those without neovascularization. Reductions in electroretinogram a- and b-wave amplitudes were found in patients with and without neovascularization. However, such reductions were of greater frequency and magnitude in patients with neovascularization. Electroretinogram abnormalities were restricted to reductions in amplitude; implicit times were generally normal. In terms of the variables of the b-wave luminance-response function, abnormalities were restricted to reductions in the amplitude variable Rmax; values of logK and n were generally within the normal range. Across all patients, there was a significant negative correlation between electroretinogram amplitude measures and capillary nonperfusion, indicating that the electroretinogram provides information about the functional consequences of peripheral capillary nonperfusion in sickle cell retinopathy.