Oil derivatives contamination of soils effects in changes of many physical properties of soil su ch as: electrical resistivity, conductivity and self potential (SP) as well. Thus the measurable a nomalies of these properties are possible to detect with geoelectrical measurements. SP geoelectrical measurements were carried out in the area of controlled oil spill. The oil was spilled into vadose zone of dry sands. The first underground water level was observed at the depth of 10 m. The measurements were carried out along 20 m long profile situated above 3 m long contaminated zone. The part of contaminated zone (1.5 m) had been subjected to bioremediation process with yeasts Yarrowia lipolytica since 4 months. In the border of contaminated zone and biodegradate done chemical gradient was developed and significant in crease of self potentials values can be observed. The measurements were carried out with potential gradient method. L und Imaging System equipment and non-polarizable electrodes (Cu/CuSO 4 ) were applied. Above contaminated and biodegraded zone distinct SP anomaly (10-20 mV) was measured. The anomaly correlates with results of EM, resistivity imaging and induced polarization investigations., Bogdan Żogała, Maciej J. Mendecki, Wacław M. Zuberek and Małgorzata Robak., and Obsahuje bibliografické odkazy