Hydatid cysts are parasitic infections caused by echinococcus granulosus and echinococcus alveolaris. These infections are characterized by cystic formations most commonly localized in the liver and lungs. These cysts demonstrate widespread hepatic, and pulmonary involvement. Rupture of the cyst due to trauma, spontaneously or during surgical intervention may lead to anaphylactic shock or even death. During hydatid cyst operations, suddenly developing desaturation, tachycardia and hypotension should lead to the consideration of anaphylaxis. These complications should remind us that patients being operated for hydatid cysts may develop anaphylaxis and preparations should be made for this complication, and dialogue with the surgical team may reduce mortality and morbidity rates. In this case report we present a patient undergoing surgical excision of hepatic hydatid cyst who developed anaphylactic shock and resulting cardiac arrest due to rupture of the cyst and traumatization of the hepatic vein.