The literature on the evolution of farming systems in West Africa shows a large diversity of general theories on rural development. The purpose of this study is to revisit the theses of Malthus and Boserup and empirically test them on a case study of Northern Cote d'Ivoire. We have at our disposal a database spread over three agricultural seasons (1995-1998) and four villages. These villages differ strongly regarding their population density and historical genesis. The comparison between these villages permits us to track down their stage in the evolution of farming systems and to identify population pressure as a key factor of the evolution of farming systems and to identify population pressure as a key factor of the evolution process of farms. Our empirical analysis shows that boserupian and Malthusian processes coexist, rather than contrast. Labor is the key factor for escaping Malthusian mechanisms and induces Boserupian innovations that are crucial to the evolution trajectory of farms.