We produced experimental renovascular malignant arterial hypertension by a modified Goldblatt's procedure in 60 rhesus monkeys (25 one-kidney model and 35 two-kidney model), and studied various macular lesions by detailed serial ophthalmoscopy, and stereoscopic color fundus photography and fluorescein fundus angiography on a long-term follow-up. The various lesions which developed in the macular region included retinal edema, cystic retinal changes, serous retinal detachment, retinal pigment epithelial changes (initially acute focal and later degenerative lesions), and lipid deposits. In addition to these, the usual retinal lesions associated with hypertensive retinopathy, e.g., focal intraretinal periarteriolar transudates, cotton-wool spots and retinal hemorrhages, were also frequently seen in the macular retina. Findings on the various lesions are described in detail, and the pathogenesis of macular edema in malignant arterial hypertension is discussed.