Search for 4th generation quarks

We present the results of searches for a new heavy 4th generation and vector-like quark using leptonic, and semileptonic final states comprising of electron(s) and/or muon(s) and jets. The full sample of 5 fb$^{-1}$ of pp collisions recorded with CMS experiment in 2011 at the center-of-mass energy of 7 TeV has been used. In leptonic final states, two same sign dilepton and trilepton channels have been explored. For semileptonic events, the search for heavy quarks is carried out using events with one lepton, and at least four jets with imbalance in transverse momenta, requiring at least one of the jet identified as originating from the fragmentation of a b-quark. No significant excess of events over Standard Model expectations is observed, therefore upper mass limits are set at 95\% C.L.