Spontaneous perirenal hematoma is relatively uncommon but may be life threatening. There are some challenges in early diagnosis due to the lack of specific presentations. We report a case of spontaneous perirenal hematoma in a patient who had histories of systemic lupus erythematosus, hypertension, and uremia with hemodialysis, and initially presented with non-specific flank pain. Dizziness and unstable vital signs were noted in the emergency room. Computed tomography and abdominal ultrasonography revealed a large perirenal hematoma over the left retroperitoneal cavity. The patient received conservative treatment without surgical intervention and had an uneventful recovery.