  We estimate the survival probability of $J/{\psi}$ in relativistic heavy-ion
collisions, using both short-distance QCD and nuclear absorption mechanism. The
suppression is found to be almost 100 percent for a thermally equilibrating
quark-gluon plasma. The measurement of such a huge suppression of $J/{\psi}$
may suggest the existence of a deconfined partonic medium, possibly a
thermalised quark-gluon plasma, at RHIC.
