Abstract: A photoendoscope comprising a telescope tube defining, near its distal end a viewing port, flash-tube assembly means connected to the distal end of the telescope tube and including a flash-tube proper enveloped in transparent protective sheath means arranged in a housing defining an aperture for transmitting light from the flash-tube proper and light conductor means extending along the telescope tube and terminating proximally of said viewing port, a barrel enclosing said telescope tube and said light conductor means at least in their distal end regions, and said flash-tube means, said barrel defining two apertures aligning respectively with said viewing port and with said flash-tube light transmitting aperture, and a transparent cylindrical sheath which is secured in said barrel, which extends for approximately the length of said flashtube proper and which covers said flash-tube light transmitting aperture, said transparent cylindrical sheath having a wall thickness which is greater where it covers said flas