Purpose: to detect a correlation between carotid system insufficiency and the presence of asymmetric diabetic retinopathy in diabetic patients.Subjects and methods: a prospective study of carotid system duplex was conducted on 20 patients with a symmetric diabetic retinopathy.Results:ipsilateral carotid stenosis to eye with more advanced changes was found in 50% of cases (10 patients), ranging 15-50% with mean 30.5% due to CCA and/or ICA.Conclusion:asymmetric diabetic retinopathy is considered the exception rather than the rule.Carotid stenosis is a predominant factor in producing it.Its identification is important in early detection of carotid system plaques and prevention of future strokes.