A 16-year-old boy is presented with the problem of free micturition, having a palpable, painless tumour spreading from the symphysis to the umbilicus. Cystoscopy revealed an impression in the vertex of the urinary bladder covered by the inflamed mucous membrane with a bulbar oedema. Fistulography showed transitional urachus persistens communicating with the terminal loops of the ileum. During surgery, a solid, fan-like fibrous connective tissue was removed, together with the vertex of the urinary bladder and peritoneum. Adhering loops of the terminal ileum were sharply separated and sutured. Histopathological examination confirmed actinomycosis of the urachus persistens penetrating into the ileum.