Cosmic ray studies with the OPERA detector at Gran Sasso

OPERA is a long-baseline neutrino experiment located in the Hall C of the Gran Sasso underground Laboratory at an average depth of 3.8 km w.e., corresponding to average muon energies at surface higher than 1.4 TeV. After a brief description of the main scientific goals of the experiment, we focus on the potentialities of OPERA used as a cosmic ray detector. In particular, we report on the measurement of the atmospheric muon charge ratio R(mu) = N(mu+) /N(mu-) and on the analysis of upgoing muons induced by atmospheric neutrinos.