Aim: To assess the effect of anticonvulsant treatment on plasma homocysteine level and lipoprotein (a) in epileptic children. Methods: Plasma total homocysteine, folate, vitamin B-12 and lipoprotein (a) concentrations were measured in 111 epileptic children taking anticonvulsant drugs for longer than 12 mo. Forty-six healthy, sex- and age-matched children served as controls. Results: Patients and controls differed significantly in concentrations of homocysteine (p < 0.05) and lipoprotein (a) (p < 0.001). The number of patients with homocysteine concentrations of >9 muM was significantly higher in the patient group than in the control group. A significant inverse relationship was found between vitamin B-12 folate levels and plasma homocysteine levels in the patient group; 28.8% of the patient group had lipoprotein (a) concentrations above the cutoff value (30 mg/dl) for increased risk of early atherosclerosis, whereas none of the control patients had concentrations above this value.