The Abdominal Actinomycosis (AA) is a rare and often unrecognised suppurative chronic illness. The diagnosis is difficult. It can have a variety of clinical manifestations and can mimic a malignancy. It's established by histology of surgical biopsy. We report a case of a 58 years old woman admitted to our institution for a pain of the right iliac fossa with a mass. The diagnosis was established after surgical intervention and histological examination. The treatment was surgical resection and antibiotherapy by amoxcillin during 6 months. The primary diagnosis of abdominal pelvic actinomycosis is difficult. All organs and anatomic structures of the abdomen can be involved. Even with extensive infection, combined operative and antibiotic therapy allows cure in most cases.