A number of papers is available reporting on a positive temperature coefficient of the resistivity (PTCR) in barium titanate near the Curie point Tc. However, the scattering mechanism leading to this effect in single crystals (1) is yet unknown. Below theoretical results a r e given for the mobility of conduction electrons where the interaction Hamiltonian of electrons with transverse optical vibrations of the rrsoftfr mode is the perturbation causing the electron scattering. A s it is shown, in this case the mobility is proportional to e is the static permittivity. Since near the Curie point the dependence 6 ' where 0 0 E (T) has an anomaly (the so-called 0 A -peak), the calculated mobility in this region has an anomalous temperature dependence involving also the PTCR effect. The interaction of the trexcesslf electron with the ions of the crystal lattice in the dipole approximation can be written in the canonical form -+ where a with the q wave vector of the j-th vibrational branch, m is the mass, z is the charge of the s-th ion in the unit cell of volume v, w,(s,qj) is the phonon polarization vector component, e is the electron charge, 9 is a reciprocal lattice vector. a are the phonon creation and annihilation operators of frequency o sj' q j q j S 8

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