The objective of this study was to determine the amplitude and temporal changes of flash electroretinogram, in nondependent insulin diabetic patients without diabetic retinopathy. Electroretinograms (Cadwell Quantum 84, Colliere) were obtained in thirty two healthy people and thirty two non-dependent insulin diabetic patients. We found decreasing time of a and b waves, in 26 diabetic patients, which suggests early retinal changes. There were no significant changes in amplitude and oscillatory potentials. The abnormalities on waves a and b were present 6.6 years after an set of diabetes; however, a relationship was not found between electroretinogram changes and duration of diabetes. In conclusion, there are decreasing times in the electroretinogram of non-dependent insulin diabetic patients before funduscopic changes are evident. Suggesting that electroretinogram may be useful to know and to follow-up early funduscopic changes in diabetic patients.