In patients presenting with a pelvic mass and an IUD in the uterine cavity, the diagnosis of actinomycosis should be seriously considered. A detailed workup, including a CT scan, endometrial curettage and biopsies where possible, should be performed before surgery. Once diagnosis has been confirmed, conservative medical treatment should be attempted before considering laparotomy, to reduce the risk of complications. Despite successful treatment with antibiotics, long-term sequelae such as hydronephrosis and renal atrophy are possible in cases of extended pelvic actinomycosis.