  This Letter presents the first search for supersymmetry in final states
containing one isolated electron or muon, jets, and missing transverse momentum
from sqrt{s} = 7 TeV proton-proton collisions at the LHC. The data were
recorded by the ATLAS experiment during 2010 and correspond to a total
integrated luminosity of 35 pb-1. No excess above the standard model background
expectation is observed. Limits are set on the parameters of the minimal
supergravity framework, extending previous limits. For A_0 = 0 GeV, tan beta =
3, mu > 0 and for equal squark and gluino masses, gluino masses below 700 GeV
are excluded at 95% confidence level.
