Aim: To evaluate the changes of the mfERG that occur in the preclinical stage of diabetic retinopathy as a predictor of early onset of diabetic retinopathy.Methods: mfERG was recorded using the RETIscan system (Roland consult, Wiesbaden, Germany) in 37 eyes of normal controls, and 51 eyes of 26 diabetic patients without retinopathy. The diabetic patients with at least 5 years of diabetes were enrolled after examination by fundus biomicroscopy and fluorescein angiography. Quadrant analysis of the amplitude and implicit time delay of P1 wave of the mfERG was used to compare between patient groups and controls.Results: The mean implicit time delay in the lower temporal quadrant was significantly different between both diabetic and normal groups (P = 0.0308). The mean amplitude of the fovea was significantly decreased in the diabetic group than the normal group (P = 0.0357). The implicit time delays in the diabetic group increased with the age of the patients and the duration of the diabetes. The glycemic control status did not correlate with the local mfERG responses. Conclusions: The mfERG peak time delays are a promising predictor for the development of diabetic retinopathy together with the duration of diabetes; especially in preclinical patients. A longitudinal prospective study may be required to confirm the findings of this study.