An intravascular pressure sensor assembly comprising: a flexible elongate member including a proximal and a distal end; a housing mounted at the distal end of the flexible elongate member; and a sensor chip (10, 100), contained within the housing, wherein the sensor chip (10, 100) comprises: a widened portion positioned within a first portion of the housing so that it substantially abuts an inner wall of the housing, and a cantilevered portion that is relatively narrow in relation to the widened portion positioned within a second portion of the housing, the cantilevered portion including a diaphragm comprising at least one piezoresistive element, the housing having an opening in the housing wall allowing pressure to be exerted upon the diaphragm, wherein the assembly includes a holding material in the first interior portion within the housing for holding the widened portion in place, wherein one or several physical features of the sensor chip are formed using photolithography in combination with DRIE processing, wherein the one or more physical features comprises: a transition between a relatively wide width of the widened portion and a relatively narrow width of the cantilevered portion thereby providing strain relief for the cantilevered portion with regard to the inner wall of the housing, wherein the transition includes a curved section such that the outline of the sensor chip (10, 100) is non-rectangular, wherein the cantilevered portion extends distally from the widened portion in a direction parallel to the longitudinal axis, the curved section of the transition curving inwardly from the widened portion towards the cantilevered portion as the cantilevered portion extends distally from the widened portion. a flexible elongate member including a proximal and a distal end; a housing mounted at the distal end of the flexible elongate member; and a sensor chip (10, 100), contained within the housing, wherein the sensor chip (10, 100) comprises: a widened portion positioned within a first portion of the housing so that it substantially abuts an inner wall of the housing, and a cantilevered portion that is relatively narrow in relation to the widened portion positioned within a second portion of the housing, the cantilevered portion including a diaphragm comprising at least one piezoresistive element, the housing having an opening in the housing wall allowing pressure to be exerted upon the diaphragm, wherein the assembly includes a holding material in the first interior portion within the housing for holding the widened portion in place, wherein one or several physical features of the sensor chip are formed using photolithography in combination with DRIE processing, wherein the one or more physical features comprises: a transition between a relatively wide width of the widened portion and a relatively narrow width of the cantilevered portion thereby providing strain relief for the cantilevered portion with regard to the inner wall of the housing, wherein the transition includes a curved section such that the outline of the sensor chip (10, 100) is non-rectangular, wherein the cantilevered portion extends distally from the widened portion in a direction parallel to the longitudinal axis, the curved section of the transition curving inwardly from the widened portion towards the cantilevered portion as the cantilevered portion extends distally from the widened portion. a widened portion positioned within a first portion of the housing so that it substantially abuts an inner wall of the housing, and a cantilevered portion that is relatively narrow in relation to the widened portion positioned within a second portion of the housing, the cantilevered portion including a diaphragm comprising at least one piezoresistive element, the housing having an opening in the housing wall allowing pressure to be exerted upon the diaphragm, wherein the assembly includes a holding material in the first interior portion within the housing for holding the widened portion in place, wherein one or several physical features of the sensor chip are formed using photolithography in combination with DRIE processing, wherein the one or more physical features comprises: a transition between a relatively wide width of the widened portion and a relatively narrow width of the cantilevered portion thereby providing strain relief for the cantilevered portion with regard to the inner wall of the housing, wherein the transition includes a curved section such that the outline of the sensor chip (10, 100) is non-rectangular, wherein the cantilevered portion extends distally from the widened portion in a direction parallel to the longitudinal axis, the curved section of the transition curving inwardly from the widened portion towards the cantilevered portion as the cantilevered portion extends distally from the widened portion.