Infrared coatings are required on both surfaces of infrared windows to increase transmission and thus enhance system performance. For certain applications, one of the surface coatings is required to have deicing, defogging, and EMI (Electro-Magnetic Interference) attenuation capabilities. This paper deals with the transparent infrared coatings, including antireflection, conductive and induced transmission coatings for application in sensor systems. The wavelength ranges covered are 3.0 to 5.0 and 8.0 to 12.0 microns. Theoretical aspects of the design techniques are discussed in detail. The experimental spectral data is presented for various coatings on various substrates. In addition to the spectral data, data on the mechanical and environmental durability of the coatings is also presented. The mechanical and environmental durabilities of the coating are very important for military systems such as electro-optical sensor systems for use on aircraft, submarines, tanks, and ships. The transparent antireflection coatings are sometimes also required to have rain erosion resistance. Data on such coatings is also presented.