The aim of this work is to investigate the pigments, the mortars and the degradation products in the wall paintings of the Forty Martyrs church, a medieval rock-hewn settlement in Cappadocia, the central region of Turkey (UNESCO Heritage). This work is part of a wider research project called “Rock paintings in Cappadocia. For a project of knowledge, conservation and enhancement of the church of the Forty Martyrs at Şahinefendi and its territory”. The study of the extraordinary pictorial complex of Cappadocia is a prerequisite knowledge necessary to carry out its conservation, restoration and valorization. It is worth stressing that the rock hewn wall paintings are the result and the peculiar expression of Cappadocia’s environmental scenic context where the permanent union between a stunning landscape and the painted churches constitutes the very identity of this area.