The aim of this study was to investigate plasma oxidant and antioxidant status in Turkish marasmic children. The study population consisted of 38 marasmic children (group I) and 28 age-matched children (group II) who were apparently well, with weight-forage >80% of the standards in the same region. After overnight fasting, venous blood samples were drawn and immediately transferred to heparinized and normal tubes. Plasma antioxidant potential (AOP), and malondialdehyde (MDA) levels were measured in both groups. The plasma MDA levels were found to be higher in group I than in group II. However, plasma AOP values were lower in group I than in group II. The present study suggests that AOP is reduced due to an impaired antioxidant system in the plasma of malnourished patients. This oxidant stress causes significant peroxidation. Also, the antioxidant defense system of the patients is deteriorated in marasmus.