Actinomycosis is a rare chronic granulomatous suppurative infection caused by an anaerobic Gram- positive bacterium, Actinomyces Israelii. Its capacity to invade surrounding tissues and to form masses might mimic other diseases. A 44-year-old woman with an intrauterine device placed 6 years ago, presents with one month history of lower abdominal pain, dyspareunia and fever. Her past medical history was unremarkable, and she had no history of previous abdominal or pelvic surgeries. Physical examination demonstrated generalised abdominal tenderness but no rigidity or guarding. Pelvic examination revealed a tender, solid, fixed pelvic mass, and no vaginal discharge.The patient was febrile. Laboratory investigations demonstrated leucocytosis, positive inflammatory markers and anaemia. Transvaginal ultrasound revealed two irregular, heterogeneous, no vascularized, solid masses, one of 70x38x63 mm and other of 62x46x33mm adhered to the posterior uterine wall with apparently normal ovarian parenchyma. Thickening of the sigmoid colonic was also found and posteriorly confirmed by a CT scan, which additionally reported a bilateral hydronephrosis and left paraaortic lymphadenopathy. The main differential diagnoses proposed for the patient were and abdominopelvic actinomycosis or advanced ovarian cancer. The patient underwent laparoscopic surgery. Intraoperative findings confirmed the radiographic diagnosis. Histological results suggested actinomycosis infectious, and no evidence of malignant process. It was performed a partial right adnexectomy and an internal double-J ureteral stents was placed. Subsequently, the patient was treated with intravenous (IV) antibiotic for 6 weeks presenting notorious improvement and was advised to continue gynecological and urological clinical follow up.