Spontaneous rectus sheath hematoma (SRSH) is a rare entity that mimics acute abdomen. Rectus sheath hematoma is the accumulation of blood in rectus sheath due to muscle or epigastric vessel injury. However, SRSH without a trauma or anticoagulation is rare. It frequently mimics acute abdomen and it may lead to misdiagnosis and unnecessary laparotomy. In this article, we described two cases of SRSH with their diagnostic and therapeutic strategy. Both of our patients in report were neither consumed antiplatelet nor coagulopathy. They both had abdominal muscle straining before their symptoms pre-sentation. We hypothesized that the SRSH may be induced by rectus muscle injury secondary to inappropriate straining or posture. To diagnose SRSH, clinical findings are important but radiologic imaging such as computed tomography, can be diagnostic. In expanding SRSH, percutaneous arterial embolization of epigastric artery is useful to secure the bleeding. If embolization is not feasible, surgical exploration hemostasis is curative. In non-expanding SRSH, it can be managed nonoperatively. SRSH is an important initial differential for acute abdomen. Radiologic imaging helps in diagnosis. Stable SRSH can be managed conservatively with good outcome.