The invention relates to a piezo-resistive pressure sensor in BESOI technology, which is particularly suited for measuring low pressures, has low linearity distortion, is made of a BESOI wafer having a first and a second silicon layer (1, 3) and an oxide layer (5) disposed between the same, has an active layer (7) that is formed by a first silicon layer (1) of the BESOI wafer, piezo-resistive elements (9) being doped in said active layer, and has a membrane carrier (11) formed by the second silicon layer (3) of the BESOI wafer, the carrier surrounding a recess (13) in the second silicon layer(3) on the outside, the recess exposing a region of the active layer (7) forming a membrane (15) and of the associated oxide layer (5), wherein in an outer edge of the region (21) of the oxide layer (5) exposed by the recess (13) a groove (19) surrounding the region (21) is provided.