Introduction /Aim: Three-dimension reconstruction of Endoscopic Ultrasound images (3D EUS) has been reported to provide additional information compared to 2D EUS. In conventional EUS, image interpretation relies on observation of a serial display of 2D images. Through 3D reconstruction, display in longitudinal and cross-section planes of imaged structures is possible. The aim of this study was to evaluate 3D EUS rendering with a new electromagnetic sensor system, and to compare it with conventional 2D images. Methods: 3D reconstruction was performed in 22 patients submitted to EUS for diagnostic and staging purposes (4 esophageal carcinoma, 1 esophageal leiomioma, 2 gastric carcinoma, 13 rectal carcinoma, 1 rectal villous adenoma, 1 pneumatosis intestinalis). Endosonography was performed with a radial scanning echoendoscope or a rigid rectal probe. While withdrawing the probe, images were transmitted to a network server. Spatial co-ordinates of the probe were continuously transmitted to the computer by a small electromagnetic sensor attached to the probe. 3D image reconstruction was performed with the Freescan 3D software (EchoTech 3D Imaging Systems GmbH, Halbergmoos, Germany). Image processing required no more than one minute. 3D images were displayed as a cube that could be manipulated by rotating and cutting the image in any plane. Results: Three-dimensional reconstruction of EUS images was achieved in all patients. Some artefacts were produced by heart motion, breathing and lack of acoustic coupling in some planes, but it was possible to obtain high quality 3D EUS images. 3D multiplanar image display provided greater detail in depicting tumor margins than 2D EUS. Conclusions: 3D EUS facilitated the assessment of local tumor infiltration and relationships to surrounding structures. This technique may improve the accuracy of tumor staging by EUS.