Actinomycosis is a chronic suppurative infectious disease usually caused by the anaerobic bacterium Actinomyces israelii. Pelvic actinomycosis is rare, and usually associated with the use of intrauterine contraceptive devices. Primary vesical actinomycosis is extremely rare. Herein, a case of a 42-year-old woman, who presented with bladder irritative symptoms and had a 13 year history of intrauterine device insertion, is reported. With the presumptive diagnosis of bladder tumor or abscess, partial cystectomy was performed. Pathological examination revealed a primary vesical actinomycosis.