BACKGROUND Abdominal actinomycosis is a suppurating affection caused by a positive Gram germ, Actinomyces israelii. Manifestations of this rare disease are usually pseudotumoral syndromes leading to surgical exeresis. The diagnosis is obtained from the histologic report. METHODS We report three cases in all of which this disease presents with tumoral symptoms. The first affected the sigmoïd, the second affected the mesentery and the last affected the greater omentum and abdominal wall. In no case, the diagnosis was done before surgery. In 2 of the cases reported here, the patients had an old, incontrolled intra-uterine device. CONCLUSIONS From a review of the literature, we observed that the diagnosis of abdominal actinomycosis remains difficult. The radiologic findings are nonspecific. Actinomycosis is treated with prolonged antibiotics, and surgery is only needed in abdominal abscess and fistula. CONCLUSIONS Theses observations illustrates the difficulties of the diagnosis of this rare unrecognized disease.