BACKGROUND: Pelvic actinomycosis is a chronic suppurative inflammatory disease caused by the anaerobic Gram-positive bacilli Actinomyces israelii. The propensity of this disease to simulate gynecological malignancies has been described previously. The great majority of these patients were diagnosed with actinomycotic diseases during or after exploratory laparotomy, but rarely preoperatively. We reviewed the literature pertaining the management of pelvic actinomycosis. CASE: A nulliparous woman with a long history of intrauterine contraceptive device (IUD) and recent Papanicolaou smear findings consistent with the presence of actinomyces presented with chronic vague lower abdominal pain, weight loss, poor appetite, and recent increase in abdominal girth associated with a large immobile pelvic mass. Transcutaneous computed tomography guided core needle biopsy established the diagnosis of pelvic actinomycosis obviating immediate surgical intervention. Intravenous and subsequent long-term oral penicillin therapy was constituted and resulted in a significant decrease in the size of the pelvic mass. CONCLUSION: In patients presenting with pelvic masses and a history of IUD placement, actinomycotic infection should be considered and diagnosis attempted by imaging guided needle biopsy. Furthermore, this case suggested that correct nonsurgical diagnosis of pelvic actinomycosis followed by prolonged antibiotic therapy might eliminate the need for extensive extirpative surgery and assist in maintaining future fertility.