This study was designed to supply data for an analysis of the network of French livestock and to build a model of spread of foot-and-mouth disease in that network. The analysis focused specifically on the initial spread, prior to the detection of the disease. The first part consisted in collecting available data on livestock, particularly on livestock movements (recorded for cattle) and then to elaborate an evaluation of the initial spread of the disease, in terms of number of infected holdings and geographical extension. This model took into account the local spread as well as the remote spread associated with the movements of animals. The study was illustrated by a comparison of two areas where the disease was introduced: Brittany and the French southeastern Mediterranean coast area. The intensity and the period of the initial spread were more important in Brittany, a region with high breeding density and higher movement activity.