Studies of the efficacy of topiramate (TPM) in infants and young children are few. Here we report an open, prospective, and pragmatic study of effectiveness of TPM in terms of epilepsy syndromes, in children aged less than 2 years. The median follow-up period was 11 months. We enrolled 59 children in the study: 22 affected by localization-related epilepsy (LRE), 23 by generalized epilepsy, six by Dravet's syndrome, and eight with unclassifiable epilepsy. TPM was effective (responders showed a decrease of more than 50% in seizure frequency) in 47% of patients, including 13% who were seizure-free at the last visit. TPM was more effective in localization-related epilepsy (48% of responders) than in generalized epilepsy (32% of responders). In the latter group, 19 patients suffered from infantile spasms. Four of six patients with cryptogenic infantile spasms became seizure-free. Of the 13 patients with symptomatic infantile spasms, only one was seizure-free. Results were poor for patients with Dravet's syndrome. In general, TPM was well tolerated. The most frequently reported adverse effects were drowsiness, irritability, hyperthermia, and anorexia. The present study concludes that TPM is effective for a broad range of seizures in infants and young children and represents a valid therapeutic option in this population.