Spontaneous intracystic hemorrhage rarely occurs in nonparasitic hepatic cysts. We describe a patient with spontaneous intracystic hemorrhage of a large simple hepatic cyst that mimicked a malignancy. A 59-year-old man presented with right abdominal discomfort. The patient's medical history included a simple hepatic cyst that had been detected 7 years earlier but was left untreated. Three weeks before presentation, right upper abdominal pain occurred but resolved spontaneously. The serum CA19-9 concentration was 48.3 U/mL (normal<37 U/mL). Ultrasonography revealed a large cystic mass, containing many hyperechoic structures and occupying nearly the entire right hepatic lobe. Computed tomography demonstrated a homogenous low-density area, 20 cm in diameter, in the right hepatic lobe. Magnetic resonance imaging revealed a heterogeneous hypointense lesion measuring 20 cm in diameter. The lesions showed linear hyperintense areas on T1-weighted sequences and mosaic heterogeneous hyperintensity on T2-weighted sequences. We suspected a hemorrhagic simple hepatic cyst, hydatid cyst, or hemorrhagic cystadenocarcinoma. Right hepatectomy was performed, and the enlarged right lobe was removed. The mass was soft, sponge-like, and contained fluid, but was not elevated. Pathologic examination of the surgical specimen confirmed the presence of a hemorrhagic benign hepatic cyst.