Ninety diabetics between eight and 18 years of age, whose diabetes is controlled very carefully, were examined by fluorescein angiography in order to investigate the incidence and severity of diabetic retinitis. At 21% the percentage was markedly lower than that found by other workers, who control metabolism much less stringently. Also the severity of the retinitis was found to be much less pronounced in our examinations than in those carried out by other groups. Our results show that besides disposition the control of diabetes plays a decisive role in the development of diabetic retinitis in young diabetics.