Over the past 20 years (1971-1990) 12 infants and children have been treated surgically for a partial or totally patent urachus in the Surgical Unit of the University Children's Hospital of Pécs, Hungary. This anomaly is of special interest to pediatric surgeons, general surgeons, urologists, paediatricians. After a short survey of the embryology and pathology of the urachus, the authors analysed their material. All but one of their patients underwent surgery without serious complications. In a 6-year-old girl the urachus recanalized following shrinkage of the bladder. The authors emphasize the need of radical removal of the partial or totally patent urachus, however, this extirpation should be carried out in a froid state, frequently following incision and drainage of the suppurating urachus.