Actinomycosis is a chronicgranulomatous bacterial infection caused by theActinomyces species which frequently manifests as cervicofacial, thoracoabdominal or pelvic infections, the latter being the least frequent. There is a strong association between long term intrauterine device (IUD) use and the development of this infection. It is characterized by the formation of slow-growing abscesses that can reach large dimensions, generating an insidious and non-specific clinical presentation. Due to the above, the diagnosis is commonly late with a direct impact on the associated complications. Antibiotic treatment is usually prolonged and surgical interventions are sometimes required. We present the case of an IUD using patient who, after several months of symptoms, was hospitalized with the diagnosis of pelvic actinomycosis. The patient evolves favorably with abbreviated antibiotic treatments and outpatient clinical follow-up.