The paper deals with the determination of plastic deformation at the grain scale. A new method is proposed. It is based on the possibility to use two EBSD maps made on the same area, before and after plastic deformation, and by using the coordinates of the triple points considered as natural markers. It is demonstrated from a theoretical example that the method could work if the triple point coordinates are known with a sufficient precision and that the mean values per grain of the deformation components, epsilon(ij,), are realistic even when there are heterogeneities inside the grains. This method is applied to an IF steel, plastically deformed in extension (15%), for two different resolution cases (small and large maps with different step sizes). The heterogeneity at mesoscale as well as at the grain scale is clearly evidenced. Lastly, the interest, capabilities and limitations of the method are discussed.