Chronically haemodialysed end-stage renal disease patients are at high risk of morbidity arising from complications of dialysis, the underlying pathology that has led to renal disease and the complex pathology of chronic kidney disease. Anaemia is commonplace and its origins are multifactorial, involving reduced renal erythropoietin production, accumulation of uremic toxins and an increase in erythrocyte fragility.Oxidative damage is a common risk factor in renal disease and its co-morbidities, and is known to cause erythrocyte fragility. Therefore we have investigated the hypothesis that specific erythrocyte membrane proteins are more oxidised in endstage renal disease patients and that vitamin C supplementation can ameliorate membrane protein oxidation.Eleven patients and fifteen control subjects were recruited to the study. Patients were supplemented with 2 x 500mg vitamin C per day for four weeks. Erythrocyte membrane proteins were prepared pre-and post-vitamin C supplementation for determination of protein oxidation. Total protein carbonyls were reduced by vitamin C supplementation but not by dialysis when investigated by enzyme linked immunosorbent assay. Using a western blot to detect oxidised proteins, one protein band, later identified as containing ankyrin, was found to be oxidised in patients but not controls and was reduced significantly by 60% in all patients after dialysis and by 20% after vitamin C treatment pre-dialysis. Ankyrin oxidation analysis may be useful in a stratified medicines approach as a possible marker to identify requirements for intervention in dialysis patients.