Abstract: The invention concerns an endoscopic instrument having a three-dimensional optical viewing system. Images from an interior body region are transmitted through image transmission elements contained within the endoscope probe to a prism arrangement. The prism maintains the images in upright position regardless of the rotation of the instrument. A shutter system operating at a predetermined frequency alternately opens and closes the optical path of each image. These images are converted to electrical pulses in accordance with the requirements of the three-dimensional television system used to display an image of the body region.