The thermopower &eegr; of Sr1−xLaxTiO3ceramics was investigated up tox=0.5 and in the temperature range between 150 K and 1200 K. In addition, the carrier concentrationnwas determined by Hall measurements and by a chemical Ti3+‐analysis. For low temperatures and highn, &eegr; depends linearly on temperature and onn−2/3, as expected from a degenerate quasi free electron gas. In the case of high temperatures and lown, the absolute value of &eegr; rises with 1.5⋅ln10⋅k/eper decade of temperature and with ln10⋅k/eper decade of carrier concentration, as expected from a classical broad‐band semiconductor obeying the Boltzmann statistics. In the range of degeneration an effective massmeffof 4.2 electron masses can be deduced without the assumption of a transport factorAe. In the classical rangeAe=3 can be evaluated, requiring only a temperature and lanthanum independentmeff. Thus, the thermopower of Sr1−xLaxTiO3ceramics can be described by a constant effective mass and a constant transport factor within a wide range of temperature and lanthanum content. Furthermore, the transition from degeneration to classical behavior can be described as a function of temperature and electron density, e.g., at room temperature it takes place at aboutx≊0.2 (i.e.,n≊3.4⋅1021/cm3). ©1995 American Institute of Physics.