Fourier transform infrared (FT-IR) spectrometry has general utility for chemical analysis. However, these analyses are limited by the requirement of the sample being accessible to the spectrometer and often undergoing some amount of preparation before analysis. This restriction has kept FT-IR from many potential applications, in particular, medical and industrial process control. The ability to make measurements at a remote site or as a reaction occurs offers a significant advance in infrared analysis. We have used a mid-IR fiber to transmit radiation outside of the spectrometer, to the sample, and then to the detector. A section of the fiber, with the protective cladding removed is used as the sampling device. In this declad region the fiber, acting as an internal reflectance element, contacts the sample and provides the chemical information for analysis. Two examples of the use of an optical fiber will be discussed. The first demonstrates the ease in which a liquid sample can be measured. The second demonstrates the use of a fiber to monitor the progress of a curing reaction in thermoset composite materials where the fiber was imbedded in the matrix. In addition to discussing the analytical utility; the instruments, fiber optic sampling, and optical characterization of the fibers will also be presented.