Topiramate (TPM) is generally recognized efficacious and safe in migraine prevention. A significant proportion of patients undergoing TPM administration may show weight loss. In epileptic subjects, high body mass index (BMI) was found to be predictive of weight loss under TPM therapy. We therefore aimed to study whether common clinical determinants may be associated to TPM weigh loss in migraine patients. In our clinical series, high BMI was not found a predictor of weight loss under TPM treatment. Unknown genetic and environmental factors that may determine the courses of weight loss under TPM therapy are still do be identified.