In this work, three titanium alloys have been studied by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM) to determine their surface topography. The alloys investigated were Ti-6Al-7Nb, Ti-13Nb-13Zr, and Ti-15Zr-4Nb, with no presence of the toxic element V, and with a possible use as biomaterials for osteoarticular prostheses. These alloys were studied at room temperature and also after a thermal treatment at 750 degreesC during 24 h, which produces a protective surface oxide layer. The aim of the present work is to compare the surface structure and morphology of the alloys, both as-received and after the oxide layer was formed at elevated temperature. (C) 2003 Elsevier B.V. All rights reserved.