Endoscopic ultrasound (EUS) elastography distinguishes tissues on the basis of their specific consistency. The preoperative diagnosis of autoimmune pancreatitis (AIP) is of the utmost importance in order to avoid surgery. The aim of this prospective evaluation of five patients was to investigate the role of this new technique in the characterization of mass lesions caused by AIP, with histology as the gold standard. All five patients with AIP presented with a characteristic stiff elastographic pattern not only of the mass lesion but also of the surrounding pancreatic parenchyma, which was not found in 17 patients with ductal adenocarcinoma and 10 healthy subjects. EUS elastography of the pancreas shows a typical and unique finding with homogenous stiffness of the whole organ, and this distinguishes AIP from the circumscribed mass lesion in ductal adenocarcinoma.