Actinomycosis is an infrequent chronic infectious disease. In most cases the diagnosis is made postoperatively because of its unusual clinical presentation. Moreover, abdominal actinomycosis may mimic cancer, inflammatory bowel disease, or diverticulitis. Delay in diagnosis leading to inadequate management and unnecessary procedures has been reported. We report the case of a 49-year-old woman with large bowel obstruction secondary to extensive pelvic actinomycosis involving the rectosigmoid and cecum. She required emergency surgery, which involved both resection and colostomy. A review of the literature on abdominal actinomycosis during the last 50 years is also reported. Rarely has emergency surgery been described in this condition. Although the incidence of actinomycosis has decreased, the abdominal-pelvic form has been increasing over the past 10 years secondary to increased prolonged use of the intrauterine device. As the clinical spectrum of actinomycosis has dramatically changed, so have the therapeutic considerations. Aggressive surgical management in advanced cases with multiorganic involvement seems to have reemerged in recent years. Consideration of actinomycosis in a woman with prolonged use of an intrauterine device and symptoms of bowel obstruction could help to improve the preoperative diagnosis and management of this rare disease.