Wall paintings have become one of the most relevant, complex and challenging research subjects in Archaeometry. Minimally- or non-invasive, accurate and multidisciplinary methods are needed to successfully address the problems posed by their physical and chemical properties and by their analysis techniques. Specifically, the analytical method implemented for the study of this type of samples must enable a precise separation of the chemical information from backgrounds and scenes, allowing the identification of pigment’s components in overlapping layers, the detection of minority components and the elucidation of pigment mixtures. Thus, this paper puts forward a multidisciplinary approach towards these goals by means of the combined use of micro Energy Dispersive X-ray Fluorescence (µEDXRF) surface mapping and single-spot micro-Raman spectroscopy and µEDXRF analysis. The samples under research come from the site of Cástulo (Linares, Spain), one of the most important Roman cities in the Iberian Peninsula. It must be emphasized the uniqueness of the walls of Cástulo, their optimal conservation state and the richness and variety of the colour’s palette used in their decoration, which make them an excellent and representative example of Roman wall paintings.