Abstract: The electron spin resonance study of erythrocyte membranes in 13 Duchenne muscular dystrophy patients and 13 age matched controls was reported.The mean value of order parameter was 0.7066 and 0.736 respectively.This data suggested that the fluidity were increased.This finding provided an evidence of erythrocyte membrane defect in D MD and supported the concept of an intrinsic defect of the lipid membranes.