The aim of this study is to describe the conservation and restoration procedures applied to the Pleistocene archaeological sites of Camino Cave, Navalmaíllo Rock Shelter and Buena Pinta Cave of Pinilla del Valle, Madrid (Spain). Clear-cut and timely decisions must be made when retrieving fossils and the close collaboration of a multidisciplinary team is the key to success. Early diagnosis is made in situ to determine the state of conservation and decay. A balance is sought between what the bones need, the available resources and the scientific data requirements of each site. The principle of minimum intervention is followed throughout the entire process. Sub-fossils that were not successfully extracted were sent to the laboratory where a new diagnosis was performed. Previously collected on-site data provide helpful information for performing treatments that ensure the material's structural stability. The last step is careful packing of the bones pending further study.