This prospective, open-label study evaluated the efficacy and safety of adjunctive levetiracetam (LEV) in Korean adults with uncontrolled partial epilepsy. Study patients had to have an average of at least 1 and not more than 14 partial seizures per month (averaged over a 3-month historical baseline) despite the use of one or two AEDs. Patients initially received LEV 1000 mg/day (administered bid) and could increase to 2000 mg/day after 2 weeks, and to 3000 mg/day after another 2 weeks, to obtain adequate seizure control. During the 12-week maintenance period, the dose of LEV could be increased or decreased once if seizure control was insufficient or tolerability warranted, respectively. Seizure count and adverse events (AEs) were recorded by patients. Global evaluation scale (GES) and quality of life (QOLIE-31) were also evaluated. A total of 100 patients were enrolled and 92 patients completed the study. The median percent reduction in weekly seizure frequency over the treatment period was 43.2%. The >or=50% and >or=75% responder rates were 45.4% and 36.1%, respectively. Seizure freedom throughout the 16-week treatment period was observed in 17 patients. On investigator's GES, 81 patients were considered improved, with 41 patients showing marked improvement. Most QOLIE-31 scales improved significantly. Treatment-emergent AEs were reported in 59 patients. Three most common AEs were somnolence (36%), dizziness (12%), and headache (8%). Adjunctive LEV therapy was effective and well-tolerated in Korean adults with refractory partial epilepsy.