During embryonic development the urachus connects the bladder with the umbilical cord. The urachus obliterates postnatally. Incomplete obliterations result in urachal cysts which, in the case of a connection to the bladder, are termed urachal diverticula. Urachal tumors are rare. We report on the case of a 46-year-old female patient with a 13-year history of recurrent bladder infections and mucusuria caused by an urachal diverticulum. After surgical resection histologic examination showed a mucus producing, intestinally differentiated adenoma within the diverticulum. This finding explains both the recurrent infections and the 10-year history of mucusuria.