Metallic materials are the most used materials as orthopaedic or dental implants for their excellent mechanical properties. However, they are not able to create a natural bonding with the mineralized bone and they could release metallic particles that could finally end in the removal of the implant. One way to avoid these effects is to protect the metallic implant with a biocompatible coating. In this work there are analyzed two kinds of protective organic-inorganic sol-gel made coatings with the adding of glass-ceramic particles with the aim of generating bioactivity. The samples are surface characterized by SEM, XRD and XPS. Amorphous hydroxyapatite (aHAp) deposited on the samples after 30 days of immersion in simulated body fluid (SBF) is detected on the samples and its presence is considered as a first signal of bioactivity. (c) 2007 Elsevier B.V. All rights reserved.