Antiepileptic drugs may cause systemic and metabolic side effects. The aim of our study was to investigate the effects of valproic acid and carbamazepine monotherapy used in the treatment of epilepsy patients on serum adiponectin and carnitine levels. The study included 60 patients, of which 30 patients receiving valproic acid monotherapy and 30 patients receiving carbamazepine monotherapy, who were followed up by the epilepsy outpatient clinic with the diagnosis of idiopathic epilepsy, and 30 healthy volunteers. Patients, who used drugs for at least 6 months, were selected. Venous blood samples were collected from the patients and healthy volunteers after their consent was obtained. Serum carnitine and adiponectin levels in the collected samples were measured using the ELISA method. Serum carnitine levels were 5166.55 ng/ml (+/- 1954.92) in patients receiving carbamazepine, 4224.56 ng/ml (+/- 2055.54) in patients using valproic acid, and 5802.64 ng/ml (+/- 3422.57) in the control group. Serum adiponectin levels were 13,606.51 ng/ml (+/- 5915.92) in patients using carbamazepine, 11,986.58 ng/ml (+/- 5367.82) in patients receiving valproic acid, and 14,033.43 ng/ml (+/- 5646.34) in the control group. In both groups, both serum carnitine and serum adiponectin levels were lower than the control group. There was a negative but insignificant correlation between the duration and dose of carbamazepine and valproic acid drug use and serum adiponectin and carnitine levels. There is a need for more extensive studies with larger sample size to investigate the effect of antiepileptic drugs used on serum adiponectin and carnitine levels.