Nucl. Instrum. Methods Phys. Res., A Nucl. Instrum. Methods Phys. Res., A 0167-5087 The TOTEM T2 telescope based on triple-GEM chambers Bagliesi M G Siena U. INFN, Pisa Berretti M Siena U. INFN, Pisa Brucken E Helsinki U. Cecchi R Siena U. INFN, Pisa David E CERN Garcia F Helsinki U. Greco V Siena U. INFN, Pisa Heino J Helsinki U. Hilden T Helsinki U. Kurvinen K Helsinki U. Lauhakangas R Helsinki U. Lami S Siena U. INFN, Pisa Latino G Siena U. INFN, Pisa Magazzu G Siena U. INFN, Pisa Oliveri E Siena U. INFN, Pisa Pedreschi E Siena U. INFN, Pisa Ropelewski L CERN Scribano A Siena U. INFN, Pisa Spinella F Siena U. INFN, Pisa Turini N Siena U. INFN, Pisa van Stenis M CERN 2010 617 134 137 The TOTEM experiment at LHC has chosen the triple Gas Electron Multiplier (GEM) technology for its T2 telescope which will provide charged track reconstruction in the pseudorapidity range 5.3<|η|<6.5 and a fully inclusive trigger for inelastic events. GEMs are gas filled detectors which combine good spatial resolution with very high rate capability and a good resistance to radiation. Preliminary results of cosmic ray tests performed at CERN on final T2 modules before installation are here presented. Comparisons between real and simulated detector performance are also shown. research-article