A 60-year old female presented to the emergency department with complaints of acute abdominal pain and lump in the right upper abdomen. Physical examination revealed a large tender abdominal lump in the right hypochondrium, extending up to the right lumbar region. Further examination revealed that the lump was parietal and not intra-abdominal. Contrast Enhanced Computed Tomography abdomen was done and a right rectus sheath hematoma was diagnosed. No predisposing factor for spontaneous rectus sheath hematoma was identified. Following an unsuccessful conservative treatment, the patient underwent surgical drainage of rectus sheath hematoma with ligation of bleeding vessels. She fully recovered, with an uneventful postoperative period and without recurrence.