A 43-year-old Asian woman who was initially seen because of hematemesis later had a gastric leiomyosarcoma diagnosed. Epigastric palpation, computed tomography, and magnetic resonance imaging assisted in determining the size, borders, and location of the tumor while a second esophagogastroduodenoscopy revealed friable gastric mucosa with erosions. Biopsy specimens taken for frozen section during surgical abdominal exploration revealed a malignant gastric stromal tumor. An en bloc excision of the mass then followed, with the final pathologic diagnosis a gastric leiomyosarcoma. Metastases were later found in the liver, peritoneum, and mesentery. Differentiation of gastric leiomyosarcoma from other stromal tumors is difficult and requires standardized nuclear and cellular evaluation of atypia, necrosis, mitosis, and tumor doubling time. The most common symptoms at initial presentation are abdominal pain and gastrointestinal bleeding. Abdominal computed tomography remains more specific in suggesting gastric stromal tumors than esophagogastroduodenoscopy and upper gastrointestinal barium series. Lymph node involvement in gastric leiomyosarcoma is rare and affords the first-line therapy of laparoscopic wedge gastrectomy with a good prognosis in tumors less than 6 cm in diameter. The prognostic factors include metastasis, size of the tumor, histologic grade, DNA ploidy of the tumor, and ulceration of overlying gastric mucosa.