In the framework of an ongoing programme, we have developed strategies to discover and characterize optical/infrared unknown counterparts to X-ray binary systems using the standard tools of the Virtual Observatory. First, we have selected some potential candidates from different X-ray catalogues. Then we have used the Virtual Observatory tools to search for optical and infrared point data sources that were coincident with the position of the X-ray source. In this work we present some examples of our ongoing programme showing the potential of the Virtual Observatory as a discovery tool.

Part of this work was supported by the Spanish Ministry of Education and Science project number AYA2010-15431, by the Vicerectorat d'Investigació, Desenvolupament i Innovació de la Universitat d'Alacant project number GRE12-35, and by the Generalitat Valenciana project number GV2014/088. JJRR acknowledges the support by the Matsumae International Foundation Research Fellowship program 2014, No14G04.