At the end of 2009 LHC started to provide p-p collisions at a centerof-mass energy of 900 GeV. About 500 k collisions events have been recorded by the CMS experiment. This paper describes briefly the performance of the tracking and vertexing algorithms as obtained by the analysis of the first data using only mesurements in the inner silicon tracker of CMS. The reconstruction of the invariant mass of several resonant states and the precise determination of the primary and secondary vertex position are the best indication that the detector is ready to face the challenging physics program of CMS
