The relationship between seizure occurrence and use of bupropion was examined on the basis of manufacturer's reports. The observed incidence of seizures with bupropion doses of 450 mg/day or less ranged from 0.35%-0.44%, depending on the method of calculation. The cumulative 2-year risk of seizures in patients receiving the maximum recommended dose of 450 mg/day or less was 0.48%. The risk of seizure appears to be higher with bupropion doses above the recommended maximum, and predisposing factors were noted in over half of the 37 reported cases. Possible risk factors are presented and recommendations are given for the use of bupropion.