Theoretical calculations are given for the electrical conductivity of graphite in the hexagonal layer planes. The resistivity increases with temperatures as T 1.2 between 25°K and 77°K. In the long wave-length limit, the lattice vibrations of graphite are approximatly grouped into two modes, polarization being in the layer plane in model 1, and parallel to the c -axis in mode 2. Contributions to the relaxation process due to the scattering of carriers by the two modes are comparable in order of magnitudes. The ratio of the electron-phonon coupling constants which gives the best agreement to the temperature dependence of the observed conductivity has been found to be C 1 : C 2 =6:1, where C i denotes the coupling constant between carriers and the i -th mode phonons. The Hall coefficient is strongly field-dependent and the present theory could not explain the positive sign of the Hall coefficient in the low field limit. Thus in discussing the Hall coefficient a more refined theory seems to be necessary.