The oxidative stress levels in plasma and hemolysate and cholesterol levels in plasma of sickle cell anemia patients, carriers and controls were evaluated. A total of 40 cases-17 patients, 13 carriers and 10 controls-were involved in the study. Plasma and hemolysate malondialdehyde (MDA) were detected via thiobarbituric acid reaction with a fluorimetric detector by high-performance liquid chromatography system. Plasma cholesterol was determined by enzymatic colorimetric method. Mean MDA levels of SCA patients were higher than those of the carriers' and healthy children's both in plasma and in hemolysate (P < 0.005). The mean plasma and hemolysate MDA levels were 25.3 +/- A 1.6 nmol/l and 86.7 +/- A 19.3 nmol/l in patients, 19.1 +/- A 0.8 nmol/l and 54.1 +/- A 10.8 nmol/l in carriers and 19.6 +/- A 0.8 nmol/l and 56.8 +/- A 9.3 nmol/l in healthy children. Mean plasma total cholesterol levels were 92.1 +/- A 19.1 mg/dl in patients, 116.2 +/- A 23.3 mg/dl in carriers and 126.6 +/- A 16.4 mg/dl in controls (P < 0.005). There was a significant negative correlation of -0.520 between hemolysate MDA and plasma cholesterol levels in patients (P < 0.05). The degree of correlation increased up to -0.782 (P = 0.008) in the patients with HbSS phenotype. This negative correlation between MDA and cholesterol may imply a potential association between oxidative stress and hypocholesterolemia in sickle cell anemia.