Fourth Generation Searches at ATLAS

Thanks to the outstanding LHC accelerator and ATLAS detector performances, 4.7fb−1 of p-p collision data with centre of mass energy 7TeV were recorded in 2011. This has allowed plenty of precision measurements but also searches for new physics. The searches for the 4th sequential generation quarks t′ and b′ using 1fb−1 of ATLAS data are presented. No excess of events above the Standard Model prediction was observed and lower limits on the b′ and t′ quark masses at 95% have been placed.