This paper presents a new interpretation of the geological and structural evolution of the largelandslide of “el Forn de Canillo” from the detailed analysis of the deep cores of soundings made over the years 2007-2009, laboratory analysis, fieldwork and background analysis of previous studies. It also presents the results of radiocarbon dating carried out of three samples. This datings, together with the published by Turu & Planas (2005), have helped to determine the age of the three major landslides that have affecte d the slope from the Upper Pleistocene, and define the relationship of the landslides with the glaciation of the area of Canillo.