Diabetic retinopathy is one of the common complications of diabetes. Unfortunately, in many cases the patient is not aware of any symptoms until it is too late for effective treatment. Analysis of the evoked potential response of the retina, optical nerve and optical brain centre will pave a way for the early diagnosis of diabetic retinopathy and prognosis during the treatment process. In this paper, diabetic retinopathy classification using transient visual evoked potential phase spectral periodicity is presented. The phase spectral periodicity of the different diabetic retinopathy patients and the corresponding latency values are computed. The results are statistically analysed and presented. © 2008 Inderscience Enterprises Ltd.