The Lys-Caillaouas massif (Central Pyrenees) forms part of the hercynian axial zone. The area has been affected by a several deformation phases, regional-, and contact-metamorphism. The metamorphic rock consists mainly of micashists, quartzites, and meta-conglomerates. This study is concerned with calc-silicate metamorphic rocks and skarn formation adjacent to the intrusive massif of different types of granites, aplites, and pegmatites. Several samples of different locations in this area have been collected to reconstruct the formation history and formation conditions of the skarn by analysing fluid inclusions using Raman spectroscopy and microthermometry (homogenisation- and melting-temperatures). Fluid inclusions were studied in grossular, quartz and vesuvianite. The skarn mineralisations, especially grossular and vesuvianite, were generated in a reducing H2O-salt-CH4-N2-rich fluid system. The minimum trapping conditions of the garnet are slightly higher (240-250 °C) than vesuvianite (160-220°C). The large variety in Th values in vesuvianite is probably caused by post-entrapment alterations due to well developed cleavages. Quartz in the skarn zone records a completely different fluid (H2O-salt), which reflects retrograde conditions and belongs to a different metamorphic event.