Investigations on UV-fibers (70 pm and 100 pm) consisting of a quartz core and a cladding of a fluorocarbon resin are discussed. The spectral distribution of the transmission is essentially given by that of the core material so that the light down to 200 nm can be transmitted at reasonable lengths. Above 300 nm the transmission values are comparable to those of regular fibers. The angular distribution of the output differs substantially from that of regular glass-glass optical fibers. Instead of a rectangular distribution expected from theoretical considerations, a bell-shaped curve has been found that is varying both with the wavelength and the optical path. UV-fibers are found to be resistant against intensive ultraviolet and X-ray radia-tion. Resistivity against chemicals, humidity, temperature cycling and continuous exposure to temperatures up to 50°C has been investigated. Finally, UV-fibers have been proved sensitive to lateral pressure, and by this effect,a degradation of the transmission can possibly occur when bending the fibers at too small radii within certain fiber optical components.