Actinomycosis is a chronic infection due to an anaerobic Gram positive commensal bacteria harbored in the healthy cavities. From the main localizations in facial, respiratory and gynecology cavities, the infection can progress forming abdominothoracic or pelvis tumors simulating pseudo-neoplastic formations. Macroscopic diagnosis of this uncommon disease is difficult even intraoperatively. The extemporaneous pathology examination confirms the presence of actinomyces grains. We report two cases of abdominopelvic actinomycosis which developed on a "forgotten" intrauterine device leading to torpid severe disease. Actinomyces are sensitive to penicillin if treatment is continued for several months but infiltrations into the urinary and digestive tract may lead to fistulae and hydronephrosis.