The Nativity scene (presépio), from the Santuário de Nossa Senhora dos Remédios, in Lamego (Portugal), is a rare and precious example of Portuguese clay sculpture from the eighteenth century. This Nativity scene presents more than 60 polychrome clay sculptures, with heights between 10 and 18 cm. The main figures show rich details and techniques, similar to the wooden sculpture decorative motives from the same century: glass eyes, lace, sequins, silver halos, glazes and metallic leafs. The presépio is contained within a wooden polychrome structure - a reliquary. Several analytical techniques were carried out in order to characterise some of the physical and chemical features of the materials. The qualitative and semi-quantitative analyses of the pigments were performed by optical microscopy and by scanning electron microscopy coupled with energy dispersive X-ray spectrometry. The technical investigation preceded the conservation and restoration of the sculptures.