Vigabatrin is an antiepileptic drug used in more than 50 countries as adjunctive therapy for the treatment of refractory complex partial seizures (rCPS) in adults. First approved in the United Kingdom in 1989, vigabatrin was approved for use in the United States by the Food and Drug Administration in 2009. Although most clinical trials of vigabatrin have been conducted in Europe, three major trials, including two pivotal trials, were conducted in the United States. These trials have demonstrated efficacy and tolerability findings similar to those observed from the European trials. Results of the US trials have demonstrated vigabatrin to be an effective and generally well-tolerated therapy for rCPS in adults, with an optimal dosage of 3 g/day for most patients, and an onset of response generally within 2 weeks. This review focuses on the design and results of the three major US trials of vigabatrin in adults with rCPS.