Abstract The potential of perovskite type thin films for applications in electronic devices or oxygen sensors strongly relies on a detailed understanding of electrical properties. While the conduction mechanisms of single crystal SrTiO 3, frequently referred to as a model system, have been widely investigated and are usually described in terms of point defect chemistry, the conductivity behavior of thin films has not been studied in detail. In this paper we report on investigations on doped SrTiO 3 thin films under varying oxygen partial pressures and at temperatures between 700 and 1000°C. The electrical measurements show remarkable results, where a sharp drop and a plateau region are the dominant characteristics in log( σ)–log( pO 2) plots. Recent investigations of the structural behavior of SrTiO 3 single crystal surfaces under certain atmospheric conditions suggested accompanying examinations by SEM and AFM, primarily addressing the morphological phenomena of the films.