The urachus is the remnant of the cloaca, which in adults attaches the bladder dome to the umbilicus. After birth it obliterates and presents as the midline umbilical ligament. Patent urachal anomalies are usually detected in childhood. In adults they occur very rarely and the presentation and diagnosis may be occasionally challenging. We present and discuss the case of an infected urachal cyst found in a 30-year-old adult.