The use of infrared non-contact temperature measurement is now an accepted technology in industry; this technology is widely accepted in the chemical, food, pulp and paper, steel and electronics industries, just to name a few. Conventional direct viewing instruments however, have a number of physical limitations which restrict their use in many applications. The utilization of fiber optic based instruments in non-contact infrared temperature measurement has extended this technology into areas considered difficult or impossible prior to the use of fiber optics. Several design considerations of fiber optic temperature monitoring instrumentation will be discussed in this paper along with their unique applications.