Abdominal compartment syndrome (ACS) is a life-threatening disorder caused by rapidly increasing intra-abdominal pressure. ACS can result in multiorgan failure and carries a mortality of 60~70%. The treatment of choice in ACS is surgical decompression. There are very few reports of ACS and experience in Korea. We report 12-year-old male patient who developed an abdominal compartment syndrome due to traffic-accident-induced retroperitoneal hematomas, Which was successfully treated by performing a bedside emergency surgical decompression with open linea alba fasciotomy with intact peritoneum. When patients do not respond to medical therapy, a decompressive laparotomy is the last surgical resort. In patients with severe abdominal compartment syndrome, the use of a linea alba fasciotomy is an effective intervention to lower intra-abdominal hypertension (IAH) without the morbidity of a laparotomy. Use of a linea alba fasciotomy as a first-line intervention before committing to full abdominal decompression in patients with abdominal compartment syndrome improves physiological variables without mortality. Consideration for a linea alba fasciotomy as a bridge before full abdominal decompression needs further evaluation in patients with polytrauma abdominal compartment syndrome.