Mucoceles are common pathological lesions of the oral cavity, usually measuring up to 10 mm. The authors describe a case of deeply located buccal mucocele measuring 35 mm in diameter. The lesion was caused by facial injury in a 54-year old man. The lesion persisted for approximately 2.5 years and was difficult to diagnose because of its unusual size and atypical clinical symptoms. Preoperative ultrasonography excluded a tumor, and this was confirmed by histopathological examination. However, oncological alertness was considered necessary on account of ulcerated mucosa next to the lesion. The mucocele was removed through surgical excision, using a scalpel and tissue scissors. No recurrence was observed in 2.5 postoperative years. It is stressed that histopathological examinations help to differentiate mucoceles from other disease processes.