Twelve patients with moderate to severe dementia and severe behavioral disorders were treated with open-label gabapentin (200-1,200 mg/day) for 8 weeks in a prospective case-series design. Patients were nonresponders to previous trials of neuroleptics. Behaviors were measured at 2-week intervals with the Neuropsychiatric Inventory (NPI), the Cohen-Mansfield Agitation Inventory (CMAI), and the Clinical Global Impression Scale (CGI). Gabapentin was generally well tolerated in this population. Although 42% of patients experienced adverse events such as gait instability and sedation, only two patients discontinued treatment prematurely because of adverse events. Average patient scores for the CMAI and the NPI remained unchanged after gabapentin. On the CGI, two patients were much improved, three were minimally improved, six were unchanged, and one was minimally worse. Gabapentin may have a role in treating a subgroup of dementia patients with severe behavioral disorders who have not responded to neuroleptics.