Let \(x,y\in \{0,1\}^ n\). Persons A and B are given x and y respectively. They communicate in order that both find the Hamming distance \(d^ n_ H(x,y)\). Three communication models, viz, deterministic, \(\epsilon\)-error and \(\epsilon\)-randomized, are considered. Let \(C(d^ n_ H)\), \(C_{\epsilon}(d^ n_ H)\) and \(D_{\epsilon}(d^ n_ H)\) be the respective minimum number of bits that must be communicated under the three models. It is shown that \[ n+\log (n+1-\sqrt{n})\leq C(d^ n_ H)\leq n+\lceil \log (n+1)\rceil. \] It is also shown that both \(C_{\epsilon}(d^ n_ H)\) and \(D_{\epsilon}(d^ n_ H)\) are lower bounded by \(\Omega\) (n), thus solving an open problem posed by Yao.