The aim of this research is to show that the insaturated fatty acids and their esters acquire quite interesting surfactant properties when they are sulfonated with SO٣ or HSO٣Cl. They are of great interest by virtue of being derived from renewable natural source in addition to their surface tension lowering, foaming power, rapid biodegradability and excellent performance in hard water. Yet, they achieve an improvement in soap behaviour in hard water. Therefore this type of surfactant can form a particularly effective synergistic system.