Pyrolysis coupled with gas-chromatograph and mass-spectrometry (PT-GC/MS) is a sensitive analytical technique allowing the analysis of different classes of compounds in crude state without the sample manipulation of derivitization. It requires a small size sample, and provides a diagnostic fingerprint of the material. Moreover, the high sensitivity, the low detection limit, and the high speed of the analysis offer a great advantage when very small amounts of samples are available, especially in the study of art objects. This paper mainly presents the use of PY-GC/MS in the identification of binding media, pigment or dyes in paintings, as well as the use to the investigation of preserved materials in art object. -- MCI