A microelectromechanical detection structure (1; 1') for a MEMS resonant biaxial accelerometer, comprising: - an inertial mass (2; 2'), anchored to a substrate by means of elastic elements so as to be suspended above said substrate, said elastic elements configured to enable inertial movements of detection of said inertial mass (2; 2') along a first detection axis (x) and a second detection axis (y) belonging to a plane (xy) of main extension of said inertial mass (2; 2'), responsive to respective linear external accelerations (a x, a y); and - at least one first resonant element and one second resonant element, having a respective longitudinal extension, respectively along said first detection axis (x) and said second detection axis (y), and mechanically coupled to said inertial mass (2; 2') through a respective one of said elastic elements, so as to undergo a respective axial stress (N 1, N 2) when said inertial mass moves respectively along said first detection axis (x) and along said second detection axis (y); wherein each of said elastic elements extends starting from a first anchorage of said inertial mass (2; 2') to said substrate, as far as said inertial mass (2; 2'); and wherein each of said first and second resonant element is anchored to said substrate at a first end thereof by means of a respective second anchorage, and is moreover mechanically connected to the respective one of said elastic elements at a second end thereof, to a connection point (c) of the respective one of said elastic elements; wherein said connection point (c) is positioned along said respective one of said elastic elements, at a distance from the corresponding first anchorage comprised between 1/100 and 2/100 of a length of said respective one of said elastic elements in a direction transverse to said longitudinal extension of the associated first or second resonant element; and wherein each of said elastic elements comprises: a rectilinear portion, extending from the first anchorage in a direction transverse to said longitudinal extension of the associated first or second resonant element, and a folded portion, which is mechanically coupled, and extends in a direction transverse to said rectilinear portion; said rectilinear portion being coupled to the associated first or second resonant element at said connection point (c). - an inertial mass (2; 2'), anchored to a substrate by means of elastic elements so as to be suspended above said substrate, said elastic elements configured to enable inertial movements of detection of said inertial mass (2; 2') along a first detection axis (x) and a second detection axis (y) belonging to a plane (xy) of main extension of said inertial mass (2; 2'), responsive to respective linear external accelerations (a x, a y); and - at least one first resonant element and one second resonant element, having a respective longitudinal extension, respectively along said first detection axis (x) and said second detection axis (y), and mechanically coupled to said inertial mass (2; 2') through a respective one of said elastic elements, so as to undergo a respective axial stress (N 1, N 2) when said inertial mass moves respectively along said first detection axis (x) and along said second detection axis (y);