Clathrate hydrates have increasingly attracted attention as a potential proton conductor because of their relatively high proton conductivity, even at low temperature. For application to various electrochemical energy devices, however, their relatively poor mechanical properties, stemming from the hydrogen bonded frameworks, will have to be improved. At the same time, any accompanying structural transformation that would cause a loss of inherent structural characteristics must be avoided. In the present work, we prepared a clathrate Me(4)NOH center dot 5H(2)O nano composite incorporating clay particles to improve its mechanical properties. It was found that clay loading induced an increase in compressive strength from 7.95 MPa for pristine clathrate to 18.25 MPa for 2 wt % clay nanocomposite. This improvement could be attributed to good compatibility between the clathrate hydrate matrix and clay particles and dispersion of the clay into the matrix on a nanometer scale. In addition, we checked the proton conductivity and potential window of the nanocomposite to confirm that they are sufficient for real applications, even at low temperature.