The work analyses observation findings in three patients with urachal cysts. On admission, two of the patients had suppurating cysts simulating the picture of the acute abdomen, one of which presented the clinical signs of acute appendicitis so vividly as to require revision of the abdominal organs. The diagnostic errors that have been made are also analysed. A conclusion is derived by the authors on the expediency of an active surgical tactics in cases of suppurating urachal cysts. They suggest extensive cyst excision with application of continuous suture and drainage of the wound to be the operation of choice.