The measurement of missing transverse momentum in the ATLAS detector, described in this paper, makes use of the full event reconstruction and a calibration based on reconstructed physics objects. The performance of the missing transverse momentum reconstruction is evaluated using data collected in pp collisions at a centre-of-mass energy of 7 TeV in 2010. Minimum bias events and events with jets of hadrons are used from data samples corresponding to an integrated luminosity of about 0.3 nb1 and 600 nb1 respectively, together with events containing a Z boson decaying to two leptons (electrons or muons) or aW boson decaying to a lepton (electron or muon) and a neutrino, from a data sample corresponding to an integrated luminosity of about 36 pb1. An estimate of the systematic uncertainty on the missing transverse momentum scale is presented. © CERN for the benefit of the ATLAS collaboration 2011.