We use the QCD sum rules (QCDSR) to study the vertex \(\eta _c D^* D^*\) . We compute the form factors considering that each one of its two different mesons can be taken off-shell alternately. The coupling constant of the vertex is evaluated through the extrapolation of the two different form factors that were thus obtained. The numerical result for the coupling constant is \(g_{\eta _c D^* D^*}=7.10^{+2.32}_{-2.69}\,\textrm{GeV}^{-1}\) .
