One form of retinopathy associated with diabetes is a proliferative small vessel process thought to be mediated by biochemical, hemodynamic, and endocrinologic factors. The authors conducted a prospective study to determine whether patients with diabetes who had proliferative retinopathy had evidence of intracranial microangiopathy visible at magnetic resonance (MR) imaging. Twenty-five patients under 40 years of age with proliferative retinopathy and insulin-dependent diabetes mellitus and 10 age-matched control subjects were studied with MR imaging. Axial images were reviewed by two neuroradiologists for the presence of white matter foci of high signal intensity. No patients demonstrated evidence of these foci. There was no evidence of ischemic foci in any of the patients (all patients were neurologically asymptomatic). The vasculopathy associated with proliferative retinopathy does not appear to affect the intracranial circulation to the extent detectable with MR imaging. The presence of white matter foci of high signal intensity or ischemic changes in the brains of insulin-dependent diabetic patients under 40 years of age should not be attributed to diabetic vasculopathy. Other causes should be considered.