Complex subsidence patterns during the mid-late Eocene of the easternmost South Pyrenean foreland are well explained by a decoupled flexure model in which upper crustal buckling is accommodated by ductile flow in the mid-lower crust while, simultaneously and independently, the lower lithosphere flexes above a ductile asthenosphere. The resulting predicted subsidence values agree with observation to well within the estimated uncertainties. The resulting lithospheric effective elastic thickness (EET) estimate (10¿3 km) is low but similar to values obtained in the South Pyrenean foreland by other authors. The separate EET obtained for the upper crust (1.5¿0.8 km) also agrees with tentative values given by other workers.