Gastrointestinal stromal tumor (GIST)is a serious and predominantly sporadic tumor of the gastrointestinal tract (GIT). We attempted to review clinicopathological and molecular findings of GIST. GIST recently has been suggested to originate from the multipotential mesenchymal stem cells. Histologically, GIST is classified into spindle, epithelioid and mixed types. Tumor size, mitotic index, anatomic location and tumor rupture are the characteristics used to predict the clinical prognosis of patients. Expressions of c-kit/PDGFRA are essential for diagnosing GISTs. Activated mutant c-kit or platelet-derived growth factor receptor alpha (PDGFRA), which are potential therapeutic targets for imatinib, are constitutively expressed in most GIST. Imatinib selectively inhibits several protein tyrosine kinases and is an effective drug in malignant GISTs. More recently, sunitinib, a new KIT/PDGFRA kinase inhibitor, has been tested in patients with GIST resistant to imatinib with promising results.