  The ATLAS experiment has measured the production cross-section of events with
two isolated photons in the final state, in proton-proton collisions at sqrt(s)
= 7 TeV. The full data set acquired in 2010 is used, corresponding to an
integrated luminosity of 37 pb^-1. The background, consisting of hadronic jets
and isolated electrons, is estimated with fully data-driven techniques and
subtracted. The differential cross-sections, as functions of the di-photon
mass, total transverse momentum and azimuthal separation, are presented and
compared to the predictions of next-to-leading-order QCD.
