The aim of this study was to evaluate the effect of haemodialysis on lipid peroxidation (the level of lipid peroxidation expressed as malondialdehyde) and endogenous non-enzymic antioxidants before and after the dialysis and compared with control group. The sampling procedure was a purposive sampling. Twenty two patients with Chronic Renal Failure (CRF) disease who were haemodialysed at 5th Azar hospital of Gorgan Dialysis Center (2005). Twenty two age and sex matched healthy control were recruited for this study. Plasma level of malondialdehyde and uric acid were significantly increased and reduced in the postdialysis group when compared with predialysis and control group, respectively (p<0.001). The plasma level of albumin and total bilirubin were significantly increased in postdialysis group when compared with predialysis group (p<0.001). The increasing level of plasma lipid peroxidation and the significant difference of non-enzymic antioxidants in the haemodialyzed pateints after the process of dialysis, maybe related with the pateint uremia, the quality of consumed water in the dialysis procedure, dialysis membrane and the loss of these antioxidants through membranes and hemoconcenteration of them during the dialysis process and the dialysis process (may increase lipid peroxidation during the dialysis process). These states of affairs may play an important role in progress of cardiovascular abnormality in haemodialyzed pateints. Due to this conditions a review of haemodialysis membrane, the techniques used in the dialysis, the consumption of various oral antioxidant, the elimination of active oxygens from the dialysis surrounding are among the measures which can prevent sudden cardiovascular abnormality in the haemodialysis pateints and ultimately these important factors up- grade the pateints quality of life and prevent sudden silent myocardial infarction.