Gastrointestinal stromal tumor (GIST) is a rare neoplasm that recently has become an intense focus of scientific investigation, as it serves as a model for the molecular therapy for cancer. Although surgery remains the principle treatment of primary localized GIST, imatinib mesylate, a selective inhibitor of KIT protein, achieves dramatic responses in metastatic GIST. Multimodality therapy integrating surgery and molecular therapy has shown promise. This article summarizes the epidemiology, clinicopathologic features, natural history, and clinical management of GIST.