In order to ascertain the first vascular lesions responsible for infantile diabetic retinopathy, 300 angiofluorographies were performed in 87 children and adolescents whose diabetes became clinically apparent before the age of 14. Compared with normal ophtalmoscopy, the angiofluorography enabled to double the frequency of the diagnosis of incipient retinopathy. In addition to the classical diabetic lesions, the authors describe modifications of vascular permeability noted by leakage of fluorescein and observed in 75% of initial retinopathies. These leakages must be considered to be the first lesions of infantile diabetic retinopathy. They appear before microaneurysms: they seem to be reversible. Highly significant correlation between degree of control, duration of diabetes and frequency of retinopathy were demonstrated.