A method for assembling a rolling bearing by deformation of the outer ring (OR) and/or the inner ring (IR) comprising, before said step of deformation, determining the theoretical position (1′, 2′) that the two extreme rolling elements should occupy so as to allow inserting at least one supplemental rolling element (11) in said space (13), said theoretical position defining an acute application angle (α2) determining the value of forces (F1) to be applied from outside to said outer ring (OR) at three application points, one central point at said nearest or contact location of both inner an outer rings in said symmetry plane and two lateral points at an angle (2α2) equal to the double of said acute application angle with respect to said symmetry plane, verifying that the deformation of the outer ring (OR) resulting from the application of said forces remains elastic and in that case, applying said forces and inserting at least one supplemental rolling element in said space.