We describe an 87-year-old woman with a large ileal gastrointestinal stromal tumor (GIST) causing hemoperitoneum. A CT scan demonstrated a large heterogeneous mass measuring about 13 cm × 11 cm in the pelvis and hemoperitoneum, with a non-uniform enhancement pattern. The mass was diagnosed as a GIST originating from the gastrointestinal tract. She underwent an urgent laparotomy and an ileal GIST with a rupture was found 130 cm from the anal to the Treitz’s ligament. Hemoperitoneum caused by ileal GIST rupture is a rare condition. Bleeding in the large tumor leading to rupture of the capsule might cause hemoperitoneum in the present case. We describe an 87-year-old woman with large ileal gastrointestinal stromal tumor (GIST) causing hemoperitoneum. A CT scan demonstrated a large heterogeneous mass measuring about 13 cm × 11 cm in the pelvis and hemoperitoneum, with a non-uniform enhancement pattern . The mass was diagnosed as a GIST originating from the gastrointestinal tract. She underwent an urgent laparotomy and an ileal GIST with a rupture was found 130 cm from the anal to the Treitz’s ligament. Hemoperitoneum caused by ileal GIST rupture is a rare condition. Bleeding in the large tumor leading to rupture of the capsule might cause hemoperitoneum in the present case.