Calcifications within primary gastrointestinal tumors are rare. Gastrointestinal stromal tumor (GIST) is an unusual nonepithelial tumor that develops in the gastrointestinal tract. In this paper we describe a case of spurt bleeding from a calcificated GIST in the stomach successfully treated by partial gastric resection. A 77-year-old man was admitted for chest discomfort and loss of consciousness. Endoscopic examination revealed spurt bleeding from the top of the submucosal tumor. No other lesions or points of bleeding were found in the stomach. Emergency partial gastrectomy was performed, and the stomach was closed. The cut surface of the tumor had a firm, solid, whitish-gray parenchyma with patchy calcification. Microscopic observation revealed a profusion of spindle-shaped tumor cells with calcification growing from the gastric muscular propria to the submucosa. The cells exhibited low mitotic activity and no prominent signs of nuclear atypia. Immunohistochemical staining of the tumor demonstrated positive reactivity for CD34, KIT, and vimentin, but negative reactivity for alpha-smooth muscle actin, desmin, and S-100 protein. Tumor cells positive for Mib-1 were rare. The diagnosis of the tumor was established as GIST.