Patients with epilepsy may manifest metabolic adverse effects throughout the course of their management with antiepileptic drugs. Leptin is a hormone that plays a major role in the regulation of feeding and energy expenditure. Leptin has been expected to form a link to weight gain in epilepsy with the use of some antiepileptic drugs. The aim of this study is to evaluate the effect of carbamazepine on body weight and serum leptin levels. This study was conducted in Izmir Tepecik Training and Research Hospital, Neurology Department. 56 epileptic patients who were on continuous carbamazepine monotherapy for at least 6 months before the study and 42 control subjects were included. Serum leptin and insulin levels were measured. Body mass index, leptin and insulin were not significantly elevated in carbamazepine group compared to control subjects (p>0.05). Our study demonstrated that carbamazepine therapy does not affect significantly body mass index, leptin and insulin. Data regarding the effect of carbamazepine on serum leptin level is limited but the results of these recent studies are correlated with ours. It can be concluded that carbamazepine is a relatively low risky antiepileptic drug in terms of obesity and metabolic syndrome but further studies are needed.