To describe the endosonographic features of gastrointestinal ectopic pancreas, especially when histopathological diagnosis is unachievable with nonsurgical modalities. Endoscopic ultrasonography was performed in 20 patients with endoscopically recognized ectopic pancreas. We then analyzed the endosonographic features of the lesions and the clinical aspects of the patients, including age, gender, symptoms, and lesion locations. Endoscopic ultrasonography revealed that the lesions originated from the second, third, and/or fourth layers of the gastrointestinal wall. Most lesions (95%, 19/20) were heterogenous, mainly hypoechoic or mixed, in echogenicity. The borders of the lesions were indistinct in 13 (13/20, 65%) and distinct in 7 (7/20, 35%) patients. Anechoic cystic or tubular structures within the lesions appeared in 7 of the 20 lesions (35%). Ectopic pancreas usually appears as a submucosal lesion with characteristic central dimpling. Furthermore, characteristic endoscopic ultrasonographic features can readily assist in the diagnosis of ectopic pancreas without having to perform endoscopic biopsy or surgery. However, either endoscopic ultrasonography-guided fine needle aspiration or endoscopic removal of lesions should still be considered mandatory for the differential diagnosis of ectopic pancreas whenever typical endosonographic features cannot be well demonstrated.