A microelectromechanical detection structure for a MEMS resonant biaxial accelerometer is provided with: an inertial mass, anchored to a substrate by means of elastic elements in such a way as to be suspended above the substrate, the elastic elements enabling inertial movements of detection of the inertial mass along a first axis of detection and a second axis of detection that belong to a plane of main extension of said inertial mass, in response to respective linear external accelerations; and at least one first resonant element and one second resonant element, which have a respective longitudinal extension, respectively along the first axis of detection and the second axis of detection, and are mechanically coupled to the inertial mass through a respective one of the elastic elements in such a way as to undergo a respective axial stress when the inertial mass moves respectively along the first axis of detection and the second axis of detection.