By means of fault population analysis (using the right dihedra, y-R diagram and Etchecopar's methods), the states of stress in a number of sites of the Cameros Massif (Northwestern Iberian Chain, Spain) and nearby areas of the Ebro Basin have been determined. These states of stress have been used as a framework in order to infer a model of the actual stress field in that area during the main stage of the Alpine compression (Oligocene-lower Miocene). The three main compression directions obtained (NW-SE, NNE, NE-SW) can be explained by a single compression field with horizontal &sgr;1 trending NNE and vertical &sgr;2, whose primary trajectories are deflected due to (1) large-scale strike-slip faults or lateral ramps of thrusts or (2) frontal ramps of thrusts oblique to the main compressive axis. The reliability of this scheme has been checked by means of a two-dimensional mathematical model based upon the finite element method and applied on a sheet whose rheological properties are similar to those of a standard limestone. This model simulates the main features of the regional stress field, and it was constructed after determining the average parameters of the possible external or ''primary'' field and simulating the major faults that could deflect the stress trajectories. ¿ American Geophysical Union 1992