With an extensive and high elevation surface (1800-1900 m a.s.l.), the Sancenas karst massif (Cantabrian Mountains) was home to a small icefield developed during late Pleistocene times. Glacial and karst processes are dominant in this region, generating many glaciokarst landforms which are uncommon in the glaciated mountains of Spain. Well-preserved moraines from outlet glaciers developed from the icefield are present. In several moraines outcrops, grain size and macro-fabric analyses were conducted to determine sediment origin and the extent of the glacial ice. An estimation of ice thickness and the position of the equilibrium line of altitude during the last glaciation were also accomplished. Three main glacial stages were identified.