Is gravitino still a warm dark matter candidate?

We make use of the phase space density approach to discuss gravitino as a warm dark matter candidate. Barring fine tuning between the reheat temperature in the Universe and superparticle masses, we find that warm gravitinos have both appropriate total mass density, Omega((G) over tilde) = Omega(DM) similar or equal to 0.2, and suitable primordial phase space density at low momenta provided that their mass is in the range 1 keV less than or similar to m ((G) over tilde) less than or similar to 15 keV, the reheat temperature in the Universe is low, T-R less than or similar to 10 TeV, and masses of some of the superparticles are sufficiently small, M less than or similar to 350 GeV. The latter property implies that the gravitino warm dark matter scenario will be either ruled out or supported by the LHC experiments.