We studied the sequence of appearance of the various fundus lesions in experimentally produced renovascular malignant arterial hypertension in 60 rhesus monkeys. The earliest lesion to appear usually was focal intraretinal periarteriolar transudates (FIPTs). Some time after that, three lesions: acute focal retinal pigment epithelial lesions, macular edema and optic disk edema, developed at roughly the same time. Cotton-wool spots appeared after these lesions. Retinal lipid deposits developed relatively late. Retinal arteriolar changes were a much later phenomenon. Conspicuous retinal hemorrhages were not a common or prominent early sign. The various classifications of hypertensive fundus changes proposed in the literature are reviewed and discussed critically, and it is concluded that, instead of using the various arbitrary grades advocated in different classifications, it is more informative and clinically useful to give a descriptive account of the individual fundus lesions revealed by ophthalmoscopy and fluorescein fundus angiography; because different lesions have different degrees of significance.