A three-year trial of Atromid treatment in exudative diabetic retinopathy was carried out in twenty-three patients and twenty-five controls. In comparison with those of the controls the eyes of the Atromid-treated patients showed a highly significant decrease in hard waxy exudates (p = < 0.0001) which was not, however, accompanied by appreciable improvement in visual acuity. No improvement in the vascular retinal lesions occurred. The initial severity of the exudative lesions was not related to the fasting serum cholesterol or triglyceride levels; there was also no correlation between the effect of Atromid on the exudates and on these serum lipids. The way in which Atromid might influence exudate deposition and its possible use in the treatment of exudative diabetic retinopathy are discussed.