Searches for long-lived particles with the ATLAS detector

Several extensions of the Standard Model predict the existence of new, massive, long-lived particles. We report on searches for particles leaving disappearing tracks in the outer tracker, weakly-interacting long-lived particles decaying to collimated lepton-jets far away from the interaction point, slow and highly ionizing particles traversing the detector, and highly-ionizing magnetic monopoles. Results of analyses using data recorded in 2011 at $sqrt{s}=7$ TeV center-of-mass energy by the ATLAS experiment at the LHC are shown.