Rectus sheath hematoma (RSH) is an increasingly common clinical condition in our hospitals due to the increasing use of anticoagulant therapies for various purposes among our patients. Treatment of spontaneous RSH is generally conservative. For continued bleeding, interventional radiologic identification and subsequent embolization is an effective option. Surgery usually involves significant morbidity and is considered a technique of last resort. In this case report, we describe the case of middle aged female who developed abdominal compartment syndrome (ACS) from a large RSH that had extended into the retroperitoneum. The patient underwent abdominal decompression with removal of the hematoma and subsequently fared very well. Patients with large RSHs extending into the retroperitoneum should undergo constant monitoring of their abdominal pressures for early detection and treatment of potentially deadly condition of ACS.