Actinomycosis is caused by Actinomyces species and is relatively rare in humans. Because of the special collateral blood flow, osteomyelitis is less common in the maxilla than the mandible. Although there are few case reports for jaw osteomyelitis, actinomycotic osteomyelitis associated with phenytoin therapy has not been reported before. The data show that antiepileptic drugs induce suppression of the immune system. This report presents a rare case of a 58-year-old man on phenytoin with actinomycotic osteomyelitis, and reviews the relevant literature.