The dependence on temperature and oxygen pressure of the electrical transport properties of the ferroelectric compound BaTiO3 doped with manganese or nickel is investigated in the temperature range 800-1100-degrees-C with an oxygen partial pressure continuously varying between 0.21 and 10(-15) atmosphere. A complex impedance analysis method has been improved for the measurements. A point defect model is proposed to discuss the different behaviour of the two dopants. The calculated conductivity is in very good agreement with the experimental data over the full temperature and oxygen partial pressure ranges. The band gap derived from this work (2.96 eV) is in good agreement with the already reported values. The ionisation energy levels of these two impurities in the band pp have been determined and compared with the values deduced from the MS-LSD calculations.