The primary objective of this work was a better insight into the electrical properties of donor doped barium titanate as a function of temperature ranging from room temperature to approximately 900°C, as well as interpretation of the results using defect chemical models. To this end, two different chemical compositions (Ba0,979La0,021Ti0,99Mn0,01O3, Ba0,979La0,021Ti1,01Mn0,01O3) were synthesized using an adaption of the Pechini method. The resulting powder was ball-milled, isostatically pressed, and sintered at 1350°C. The disk-shaped pellets were contacted via thin layers on the top faces and characterized by impedance spectroscopy as a function of temperature and oxygen partial pressure. Apart from the conductivities of bulk and grain boundaries, the dielectric constant was obtained from the impedance measurements and interpreted in terms of the Curie-Weiss-law.