This study was investigated to evaluate the level of malondialdehyde, ascorbic acid and membrane potential among diabetic patients in Owerri.100 diabetics patients and 100 apparently healthy subjects between the ages of 45- 60 years admitted to General Hospital Owerri were selected in this study. Fasting venous blood was collected and was used for the determination of malondialdehyde, ascorbic acid and membrane potential. The results obtained revealed that the levels of malondialdehyde was increased in diabetics when compared with the control. While membrane potentials and ascorbic acid were significantly decreased in diabetics patients when compared with the control at P<0.05. This could probably imply increase of malondialdehyde and decreased membrane potential as well as decreased ascorbic acid could lead to oxidative stress.