A diagnosis of intracranial actinomycosis was made in a 9-year-old boy with headache, cranial nerve dysfunction and ataxia. Poor dental hygiene leading to caries and an inflammation in his right upper jaw probably was the cause of cervicofacial actinomycosis with intracranial extension. A full recovery was achieved by treatment with benzylpenicillin. Actinomyces is a gram-positive bacterium belonging to the endogenous flora of the mucous membranes of the oropharynx, gastrointestinal tract, and female genital tract. Disruption of the mucous membrane is the portal of entry for an extremely destructive infective process that is effectively treated with penicillin. Good orodental hygiene is important for the prevention of actinomycosis.