  Virtual effects of gravitons in the production of diphotons at the upgraded
Tevatron and at the LHC are analysed with the idea of probing the parameter
space of the Randall-Sundrum (RS) model. It is shown that this process yields
stringent constraints on the parameter space of the RS model. We show that data
on diphoton production from Tevatron Run II will be sensitive to a masses of
the first graviton resonance in the range of 700-1150 GeV, while at LHC the
mass range probed will be in the region of 3.5 -- 5.5 TeV.
