The present study considers the evolution of consanguinity in the Vallouise, a high glacial valley in the French Alps. The genealogical method was used to estimate consanguinity in this Alpine population from the 17th to the 19th centuries. This method was then compared with three other methods used to measure consanguinity. The results indicate that while consanguinity increased through time (marriage dispensations and genealogies), the structural consanguinity (isonymy) was very stable throughout the entire period.