In mountains, domestics and wild ungulates share not only alpine pastures but also can exchange pathogens. Here, we studied the consequences of the presence in chamois (Rupicapra rupicapra) populations of bacteria which cause troubles in the reproduction of small ruminants. First, we took into account individual or environmental factors known to influence reproductive success of female chamois. Then, we searched whether the presence of Salmonella Abortusovis, Chlamydophila abortus and Coxiella burnetii, three bacteria which cause abortions and neonatal mortality in sheep, goat and cattle, influenced the chamois reproductive success. At the individual level, only the presence of antibodies against Salmonella was linked with a decrease of reproductive success. However, at the population level, interactions between the seroprevalence of the three infections indicated that these bacterial diseases influenced the chamois fecundity.