Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasm in the gastrointestinal tract. Computed tomography plays an important role in the diagnosis and staging of these tumors. Furthermore, computed tomography is also the imaging modality of choice for monitoring the effects of treatment and detecting tumor progression after treatment with imatinib, a tyrosine kinase inhibitor. This article summarizes computed tomographic features of GISTs and response evalua- tion criteria, including Response Evaluation Criteria in Solid Tumors (RECIST) and Choi criteria.