Epilepsy is a chronic disorder often requiring years of treatment. Accordingly, adverse effects of epilepsy and its treatment can impact general health for many decades. The psychological consequences of epilepsy are well documented, although the metabolic consequences of the treatment of epilepsy have only recently received attention. Antiepileptic drugs (AEDs) are well known to alter weight, causing either weight gain or weight loss. The mechanism by which this occurs remains to be fully understood, although there appears to be an effect on lipid and glucose metabolism. This chapter examines current data available on the adverse effects of individual AEDs on somatic weight, serum lipid profile, and glucose metabolism. These issues are of importance to neurologists caring for patients with epilepsy.