First Version, April 29, 2013. Chapter ANALYSIS OF CULTURAL HERITAGE MATERIALS BY INFRARED SPECTROSCOPY Andrea Poliszuk and Gabriel Ybarra 1 Instituto Nacional de Tecnología Industrial, San Martín, Argentina ABSTRACT Several Fourier transform infrared spectroscopy (FTIR) techniques are available for materials characterization. These analytical techniques, which include transmission, attenuated total reflection, reflection, reflection-absorption, and microspectroscopy, are routinely used for the identification of industrial coatings in which synthetic polymers are used as film forming materials. However, the identification of cultural heritage materials by FTIR is cumbersome because of the combination of natural materials and the techniques employed by the artists and craftsmen, as well as the effects of aging and deterioration of the materials. In this chapter, we aim at the identification of cultural heritage materials employing widely available FTIR techniques, with special emphasis on the optimization of ease of sample preparation and high spectral quality. Selected examples from cultural heritage pieces, such as pre-Columbian rock pictographs, XIX century papier-mâché models, mural paintings, easel paintings, and historic buildings are presented to illustrate how infrared spectroscopy can be a helpful tool for the cultural heritage conservation. The interpretation of the infrared spectra permits to identify the materials and techniques used by the artists and craftsmen of the past. This information can be then used by conservation experts to carry out proper preservation or restoration actions. Keywords: Conservation; Cultural Heritage; Infrared Spectroscopy