There are a host of fiber-optic delivery devices available for use with the Er:YAG, HF, CO, and CO2 lasers at 2.9, 2.8, 5.3, and 10.6 microns wavelengths, respectively. While many of these fibers are not as convenient to use as conventional silica fibers, they offer the ability to deliver infrared laser energy for a wide variety of medical applications. The fundamental attributes of fluoride glass, chalcogenide glass, single-crystal sapphire, and polycrystalline silver halide optical fibers are reviewed and their practical properties tabulated.