[en] Surfactants are an important class of chemical products in view of the volumes sold and of their great variety of applications. Biosurfactants produced by microorganisms, and surfactants derived from renewable raw materials are coming progressively onto the market. Considering their many properties and large field of applications, their development needs extensive cooperation across disciplines (chemists, physicochemists, biologists, product developers, formulators...) in order to fully characterize them (chemical structure, surface activity, self assembly properties...) and identify their potential uses. New value adding opportunities will result from the identification of specific activities of biosurfactants, especially in relation with their biological effects (antibiotic, antifungal, insecticide, antiviral and antitumoral agent, immunomodulator or specific toxins and enzyme inhibitors). (C) 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.