  We obtain the entropy of a static spherically symmetric wormhole from the
entropy of matter consisting it. Some exact wormhole solutions are analyzed in
detail and their entropies are obtained. We display the asymptotic forms of the
entropy for solutions having regular asymptotic regions in which matter spreads
to infinity. In the analysis, we find that the combination of ADM masses
$\mathcal{M}\equiv \alpha_+ M_+ + \alpha_- M_-$ plays an important role in
thermodynamics of a wormhole, where $\displaystyle \alpha_\pm \equiv \lim_{r\to
\infty} \sqrt{-g_{tt}}$ in the upper/lower half, respectively.
