Pech de l'Azé is a group of caves and rock shelters near Sarlat, in the Dordogne district of south-west France. In the cave Pech I there occurs a remanent of breccia containing Mousterian (middle Palaeolithic) artefacts of Denticulate and Typical varieties, overlying a travertine layer. We have used the 230Th/234U dating method to determine the age of this travertine: 123±15 kyr. This age is consistent with deposition of this travertine during isotope state 5e, the warmest substage of the last interglacial. We show here that this result is consistent with geological and palaeontological estimates of the age of sediments filling the cave1.