This paper attempts to highlight the need to incorporate geomorphological elements into the management of protected natural areas, as a major element in the articulation of the natural system. The geomorphological heritage is constituted of sites of interest called Geomorphosites that included scientific but also added, cultural or scenic values, which make them authentic heritage resources. For assessment of geomorphosites, a semi-quantitative methodology based on the intrinsic added value and use was been applied. The study focuses on inventorying and evaluating geomorphosites in Parque Natural de Valderejo (Alava, Spain). Five geomorphosites have been inventoried and evaluated in Valderejo; for each site an assessment was conducted proposals are for management and use are provided for a few sites. The methodology has proved useful as a means to inventory, diagnose and define proposals for better management of the geomorfosites in Parque Natural de Valderejo, and could be applicable for other protected natural areas.