Rupture into the abdominal cavity is a rare but serious complication of hydatid disease that necessitates emergency surgical intervention. We present herein a case with mild abdominal symptoms due to hydatid cyst rupture into the peritoneum after trauma. A 24-year-old man was admitted to the emergency room with mild abdominal pain. His symptoms had started after a fall four days earlier. Ultrasonography and computed tomography showed cystic lesions in the liver and peritoneum with intraabdominal free fluid. He was treated surgically with partial cystectomy and falciformoplasty. Postoperative albendazole therapy was given for two months. There was not recurrence four months postoperatively at control computed tomography.