Infrared spectroscopy has been used successfully in the characterization of several types of painting materials. Although most often employed with organic materials, the technique can also yield valuable structural information on many inorganic compounds. Several applications of infrared spectroscopy to inorganic pigments are reviewed, the theoretical bases for the spectra of these materials considered, and characteristic spectra presented. The materials discussed include chrome greens, green earths, and chromium oxide and viridian. Synthetic organic pigments can also be readily identified by infrared spectroscopy and one example (phthalocyanine blue) is discussed. All spectra were obtained from minute samples comparable in size to those often available from art objects, and were recorded using a Fourier transform IRspectrometer.