Near infrared spectroscopy (NIRS) could open the way to a fast, reliable, and ecological method for distinguishing between treated and untreated wood. In this study, Maritime pine (Pinta pinaster) strips were treated with four commercial wood preservatives containing organic (cypermethrin, IPBC, permethrin, propiconazol, tebuconazol) and inorganic (boric acid, copper) active components. NIRS information was enhanced by applying the pre-processing procedures: first and second derivatives (Pt D., 2nd D.), multiplicative scatter correction (MSC), standard normal variate (SNV), and their combinations. Principal component analysis (PCA) was then applied to separate between strips. In our findings, 1st D.+MSC and 1st D.+SNV combinations were the pre data processing methods best able to distinguish between treated and untreated Maritime pine strips. This research shows the potential of NIRS technique when combined to multivariate analysis, which provides rapid and efficient identification of untreated and treated Maritime pine wood.