Pelvic actinomycosis is a chronic granulomatous suppurative disease caused by an anaerobic gram-positive organism Actinomyces israelii usually associated with intrauterine devices. Systemic lupus erythematosus is an autoimmune disorder associated with multiple primary and drug-related immunological defects that predispose patients to infections. The combination of both diseases in a postmenopausal patient is a rare occurrence. A case of a pelvic mass in a 49-year-old postmenopausal patient with systemic lupus erythematosus treated with immunosuppressive therapy for two years is presented. The patient presented with lower abdominal pain to the gynecology clinic and was found to have a pelvic tumor. She had no history of intrauterine device use. Histopathologic examination of the laparotomy specimen revealed pelvic actinomycosis.