Resumen
We are conducting a spectroscopic monitoring of O- and WN-type stars for which there is no indication of multiplicity in the Galactic O-Stars Catalog (Maíz-Apellániz et al. 2004) or in the VIIth Catalog of Galactic Wolf-Rayet Stars (van der Hucht 2001). We search for radial-velocity (RV) variations indicative of orbital motion.