turbid solutions were significantly found for high diesel content (>50%) and high E/S content (>50%). This result indicates that the higher EO group of the surfactant influence on miscibility of the system due to its higher hydroelectricity (see Fig. 1). However, for the system with LS 7, larger the area of transparency and homogeneity were observed at the E/S ratio at 1. This can be explained by the Bancroft’ Rule that states the increasing hydroelectricity of a surfactant increases the amount of the surfactant needed to obtain reverse mi cellar micro emulsion [31].