Actinomycosis is a chronic suppurative bacterial infection produced by Actinomyces israeli. The three major clinical presentation include the cervicofacial, thoracic, and abdominal regions. Abdominal actinomycosis is a rare entity which presents some difficulty in establishing a correct preoperative diagnosis. The diagnosis is usually based on histologic demonstration of sulfur granules in pus or surgically resected specimen. Recently, authors experienced a case of actinomycosis of the greater omentum in 38-years old woman. The patient underwent surgery under the impression of periappendiceal abscess. A 6cm sized firm mass was noted in the transverse colon. Histologically the mass was composed of fibroinflammatory mass with multiple actinomycosis granules.