  We consider gluon and gluino scattering amplitudes in large N beta-deformed
N=4 SYM with real beta. A direct inspection of the planar diagrams shows that
the scattering amplitudes to all orders in perturbation theory are the same as
in the undeformed N=4 SYM theory. Using the dual sigma-model description, we
find the same equality at strong coupling to all orders in the sigma-model loop
expansion. Finally, we show that the same analysis holds for gluon scattering
amplitudes in a three-parameter deformation of planar N=4 SYM that breaks all
the supersymmetry.
