Lesional epilepsy is thought to be a direct consequence of focal brain lesions of dysgenetic, neoplastic, vascular, or traumatic origin. It has been estimated that at least half of all epilepsies are the result of such lesions. The current discussion includes an overview of the cognitive and behavioral presentations in adults with epilepsy secondary to focal pathology. The neuropsychological presentation in this population is influenced by many factors, including the location and nature of the underlying lesion, seizure characteristics, the effects of treatment, and patient variables. Few studies attempt to disentangle the specific contributions of these variables to cognitive performance. However, where available studies examining the separable effects of seizure-related variables on cognitive functioning in individuals with lesional epilepsy are also reviewed. This overview includes a discussion of focal malformations of cortical and vascular development and select foreign tissue and acquired lesions.