Topiramate is an anticonvulsant agent effective in the prophylaxis of migraine, which also induces weight reduction by an unknown mechanism. We investigated the effect of topiramate on resting metabolic rate, anthropometric measurements, and body composition in patients with migraine independently from any intention to lose body weight. Forty patients (18-71 years old) with migraine were treated with 100 mg of topiramate/day over a period of 3 months. Anthropometric measurements, body fat proportions and resting metabolic rates of these patients were measured before and after treatment. At the end of 3 months, we detected mean 0.8 kg reduction in body weight and 0.3 kg/m(2) reduction in body mass index (BMI). Waist circumference decreased significantly (p = 0.01). Body fat ratio decreased (p = 0.016). Abdominal skinfold measurements decreased after treatment (p = 0.048); however, no difference was found in other regions (p > 0.05). We did not find a significant difference in resting metabolic rate (p > 0.05).These TPM-treated patients lost weight and had reduction in their mean BMI. It was seen that patients lost weight from body fat tissue and central area. We saw that TPM'S weight-reducing effect was independent from resting metaobolic rate. The weight-reducing effect of TPM may result from changes on the hypothalamus.