Actinomycosis is a granulomatous suppurative bacterial disease caused by anaerobic actinomyces, which presents primarily with the cervico-facial, thoracic, abdominal or pelvic form. Cutaneous involvement is well documented and it is usually secondary to local extension or exceptionally to ematogenous spreading from visceral sites. Primary cutaneous actinomycosis is very rare and usually associated with external trauma and/or local ischemia. We report on the case of a primary cutaneous actinomycosis of the forehead in a 59-year-old man with diabetes mellitus who had had a preceding cranial trauma and several cutaneous reconstructive surgical procedures. The patient was treated successfully with combined antibiotic therapy.