the cause of the demise of the Neandertals, the well-known middle Pleistocene population, is the topic of an unresolved debate.the demographic differences between Neanderthals and modern humans (fecundity rate or diversity in timing of maturation) mayhave had a major impact on this demise. the aim of our study is to analyze this phenomenon using a demographic approach inaccord with the hypothesis that the Neanderthal population was already demographically weakened or endangered when modernhumans arrived in Europe. We began [1, 2] to analyze this phenomenon in terms of a very simple demographic approach in orderto test the hypothesis that demographic variations in fertility and/or survival rates might have led to a reduction in the size of theNeanderthal population. In this paper we propose a more complex model on the basis of animal ecology, aiming to identify param-eters that correspond to the decay and extinction of the Neandertal population over a period of 10,000 years, beginning from aninitial population of 70,000 individuals, which were divided into at least three geographical subgroups [4, 5], the first correspond-ing to southern Europe, the second to central Europe, and the third to eastern Europe and Asia. We used the Leslie matrix whichrequires the survival, the fertility and the migration rates for each age group. Since the demographic rates for the Neanderthalsare unknown, we used a random selection from a beta distribution of each parameter for each age group, for each geographicalsubgroup, and for each of the 10,000 years. the model we have developed allows us to affirm that very small changes in fertilityand / or survival rate are sufficient to account for the disappearance of the Neandertal population. Among these subgroups, theeastern European subgroup was the first to disappear, followed by the demise of the central European subgroup and finally by thatof southern Europe. this study is part of the multidisciplinary project NEDEMO (Neanderthal Demise Modeling), which aimsto identify the demographic parameters (fertility, survival rates, structure and variation in population size) that would have causedthe disappearance of the Neandertal population