The periodontal condition of 40 adult epileptic subjects (mean age 51 years) receiving long-term therapy (mean 18 years) with phenytoin (PHT) or carbamazepine (CBZ) was studied. The subjects completed a questionnaire and underwent clinical and radiologic examination. Patients receiving PHT exhibited the same level of alveolar bone loss as those receiving CBZ. Patients receiving PHT exhibited more units with gingival overgrowth, reflected by the significantly higher number of gingival units with increased probing depth (p < 0.05). The results indicate that long-term PHT does not result in increased risk for alveolar bone loss as compared with CBZ.