Epidermal inclusion cyst in the mandibular ramus is a very rare condition. Intraosseous epidermal cysts are benign cysts appearing clinically as radiolucent lytic bone lesions. Definitive diagnosis is made with histopathologic examination. Treatment is simple curettage and grafting if the defect is large. We present a case of a 78-year-old man who was admitted to our clinic with the complaints of swelling in the cheek and preauricular area of 8 years' duration. In computed tomography scan, a cystic mass measuring 6.5 × 4.5 cm with necrotic center causing expansion in the left ramus mandibula and thinning and rupture of the cortex was found. The mass was reported to extend to the zygomatic arch superiorly and masticator space minimally. Simple curettage was performed. Histopathologic examination revealed epidermal inclusion cyst. A case of mandibular ramus epidermal inclusion cyst is presented.