Background/Aims: Endoscopic ultrasonography (EUS) has been useful in evaluating submucosal lesions of the upper gastrointestinal tract as well as providing guidelines for therapeutic plans. Large proportions of submucosal tumors are diagnosed as stromal tumors. Most are benign, but a significant proportion of them could be malignant. There are a few reports concerning EUS findings as being predictive of malignancy. The aim of this study was to evaluate specific EUS features favoring malignancy in stromal tumors of the UGI tract. Methods: From January, 1992 to June, 1997, thirty-three cases appeared involving stromal tumors (18 benign, 15 malignant (including 8 STUMP)), and were either surgically (27 cases) or endoscopically (6 cases) resected. Videotapes and photographs were reviewed and EUS features that favored the malignancy were analyzed. (Korean J Gastrointest Endosc 18: 825-831, 1998) (continue)