Primary vesical actinomycosis is an extremely rare disease. In most cases it is misdiagnosed as vesical or urachal tumor and usually diagnosed through post-operative pathologic confirmation. Here we report a case of primary vesical actinomycosis confirmed by preoperative repeated multiple transabdominal biopsies. The patient was a 49-yr-old woman who presented with frequency, dysuria, and intermittent gross hematuria for 2 months. Computed tomography and cystoscopic examination showed broad-based, edematous, and protruding mass at the dome and anterior portion of the bladder. The clinical and imaging findings of the patient initially suggested vesical malignancy. Transurethral resection and multiple biopsies of the mass were performed. Pathologic examination demonstrated fibrosis with chronic inflammation. We performed repeated transabdominal multiple needle biopsies for further pathologic confirmation. Histopathologic examination demonstrated typical sulfur granules, which were consistent with actinomycosis.