The science of agroecology, which is defined as the application of ecological concepts and principles to the design and management of sustainable agroecosystems has known these last years a tremendous renewal of interest among the community of agricultural scientists but also amongst policy makers. This is mainly due to the important ecological disservices and often failure to ensure food security provided by intensive modern agriculture and associated techniques based on the combined use of agrochemicals and high-yielding varieties in monocropped systems. The main principle of agroecology consists in assembling and increasing functional biodiversity in agroecosystems to enhance synergisms in order to provide various categories of ecological services such as the activation of soil biology, the recycling of nutrients, and the enhancement of beneficial arthropods and antagonists. Functional diversity may be enhanced through different practices and strategies which include crop rotations, cover crops, intercrop ping, crop/livestock mixtures, agroforestry mixtures, etc. New strategies incorporating ecological knowledge gained from the observation of natural ecosystems and or traditional agroecosystems may be a credible alternative to design such innovative systems. Designing such novel agricultural systems calls for in-depth knowledge of biological regulations in ecosystems, but also for the integration of traditional agricultural knowledge held by local farmers. Integration of these two aspects is one of the challenges that agricultural science has to deal with today. In addition, although practices are ap plied at the plot and / or farm scale by farmers, their efficiency and associated services are expressed mainly at the landscape scale. This paper reviews the main initiatives that lie behind these trends, analyzes the basic concepts underlying the design of such systems, and suggests new frameworks for action that include Nature observation, experimental and model-b