An endoscope test bench is presented to test the optical quality of endoscopes on a regular basis to assure optimal image quality during surgery. A power LED and a photo diode are used to measure the transmission of the illumination fibers. Captures of target images displayed on a LCD screen as seen through the endoscope with a high resolution camera are analyzed to determine the contrast for different spatial line pairs. Transmission and contrast plots are compared to reference data to determine whether an endoscope is still acceptable for clinical application. Results show that endoscopes degrade gradually but steadily over time. In time a large database of various types of endoscope will be built to fine-tune the criteria for approval or rejection of the endoscopes.