The prompt production of &chi / c quarkonia is studied in proton-proton collisions at 7 TeV, using data collected by CMS in 2011 corresponding to an integrated luminosity of 4.6 fb &minus / 1. The &chi / c mesons are reconstructed through their radiative decays to J/&psi / and photon with J/&psi / &rarr / &mu / +&mu / &minus / . The photons are reconstructed through their conversion in electron-positron pairs in the tracking detector which gives a mass resolution sufficient for resolving these states. The ratio of the prompt production cross sections for the &chi / c1 and &chi / c2 states, &sigma / (&chi / c2)/&sigma / (&chi / c1), has been determined as a function of the J/&psi / transverse momentum between 7 and 25 GeV/c.