Gastrointestinal stromal tumors are the mostly seen mesenchymal tumors of the gastrointestinal system and mostly seen at the stomach. We report a case of giant gastrointestinal stromal tumor of the stomach in a 71-year-old woman. The physical examination and radiological findings revealed that a giant mass occupied most of the abdominal cavity. The patient underwent an en-block resection of this giant mass with partial resection of the distal stomach and transverse colon and, reconstruction with gastro-jejunostomy and end-to end colo-colic anatomoses. The histopathologic diagnosis was revealed as gastrointestinal stromal tumor of the stomach. We suggest that complete surgical resection is the only effective radical treatment approach for giant gastrointestinal stromal tumors of the stomach.