A 38-year-old woman was admitted to our hospital due to severe anemia. CT showed a 13×12 cm tumor with moderately enhanced wall thickening in the right upper abdomen. The huge tumor located adjacent to the jejunum and compressed the right transverse colon. Hemorrhagic necrosis and air were observed within the tumor, suspecting tumor penetration into the jejunum. The patient was diagnosed with abdominal GIST with jejunal infiltration. Laparotomy revealed a 13× 11 cm solid mass with intra-tumoral hemorrhage and invasion into the jejunum, located in the transverse mesocolon. Tumor resection combined with partial jejunectomy and transverse colectomy were performed. Immunohistochemical findings of the resected specimen was positive for c-kit and DOG-1, and the MIB-1 positive rate was 10%. Three weeks after the operation, re-anastomosis was performed due to transverse colon anastomotic stricture. She was discharged 45 days after first operation. Currently, 9 months after the operation, patient has been prescribed imatinib and is alive without recurrence.