Zinc oxide (ZnO) crystals have recently drawn attention due to a relatively low price and to their application perspectives in optoelectronics. One of the most cheap and simpler methods for obtaining such high conductive crystals is the chemical vapor transport (CVT) in sealed chambers. Recent progress for CVT growth of high quality ZnO crystals based on HCl/HCl+H2 transport agents has given possibility of obtaining materials with controllable electrical parameters and impurity composition varied in a wide range [1,2]. Features of impurity band and electron mobility in these high doped crystals are interesting for fundamental science and possible applications in optoelectronics. HCl/HCl+H2 transport agent density was varied in the 0.2-3.5 atm range. The growth temperature of crystals was 1050 °C. The thermal annealing of ZnO:HCl samples was carried out in air at 1050 °С, during 24 hours, for minimization of concentration of hydrogen impurity and intrinsic defects of oxygen vacancies. Conductivity (), the Hall coeficient (RH) and Hall mobility (μ) were calculated from the Hall effect measurements in the 20-300 K temperature range using a six-probe method. The activation energy of donors caused by Cl impurity (ED), the concentration of donors and ionized impurity centers (Ni), and the compensation degree were calculated from the Hall effect measurements for samples with verious doping level. It was found, that ED value in low doped samples is about 68-9 meV. It has a linear dependence on Ni1/3 with coefficient of about (4.5-0.5)-10-8 eV-cm. Features of RH(1/T) dependences caused by the presence of impurity band were also observed (Fig. 1(a)). New effect of the strong decrease of RH at lowest temperatures in the most doped samples was found. The polar-optical phonon scattering, acoustic phonon scattering via the piezoelectric potential and via the deformation potential as well as ionized and neutral impurity scattering were investigated for mobility of conduction band electrons (Fig. 1(b)). Best fit gave donor activation energy of 67 meV, longitudinal elastic constant of 205 GPa, piezoelectric coefficient of 0.21, deformation potential of 3.8 eV, effective polar-optical phonon temperature of 750 K, electron polaron mass of 0.27m0, high-frequency dielectric constant of 3.7 and static dielectric constant of 7.8.