Actinomycosis is an infrequent chronic progressive granulomatous and suppurative disease. This infection is caused by Actinomyces israelii, normally present in healthy individuals. We present a rare case of a combined intra- and extra- abdominal actinomycosis in a 50 year old female patient, with no underlying predisposing factors. The patient complained of a right lower quadrant pain. Although we first diagnosed a peri-appendiceal abscess, the CT scan suggested a right colon tumor. The patient underwent segmental colectomy and the histological examination of the specimen revealed colon actinomycosis. A review of the possible pathogenesis and therapeutic modalities is also presented.