We report a study on 809 births and 885 deaths collected from the civil registries of the Pyrenean village of Beost, Ossau Valley, Bearn, France, during the entire 19th century. Among the studied parameters, some give us interesting data on the population history. Thus, the rate of mortality under 1 year of age (110,7 per thousand), the global longevity of this population (mean age at death: 45,8 years) and the absence of significant increase in mortality during the winter months and periods of difficulty for food availability argue in favor of a quite satisfactory sanitary level. Nevertheless, the reduced longevity of illegitimate children (nine deaths often before the age of 7) suggests an absence of care for this population category who was socially rejected. Furthermore, the proportion of women dying between 21 and 40 years of age was twice than that of men, which could be explained by maternity-related medical complications. The seasonality of births (and therefore of conceptions) is less typical than in the other mountain populations. Finally, we may note an increased mortality at the end of 1856 due to a cholera epidemic and in 1870 because of small pox.