Hydatid cyst disease is caused by Echinococcus granulosus, a common parasitic infection of the liver. Most common sites are liver (70%), lungs (25%), spleen, kidney etc. i.e. can be found in any region of the body, from brain to inguinal canal. Intra-peritoneal hydatid cyst is found only in 13%, usually secondary to rupture of primary hepatic cyst. Primary intra-peritoneal hydatid cysts are rare (2%). Primary hydatid cyst of omentum with rupture is a rare presentation in emergency department and not reported in literature.