A flexible coupling for coaxial shafts which comprises two facing flanges (14,15), one for the driven shaft (31a) and one for the driving shaft (316), and blocks of elastomeric material (26) which are rigidly coupled between the flanges (14,15), the elastomeric blocks (26) having a substantially triangular shape, being arranged radially, and being fixed to a flange (14) so that one vertex is directed toward the center of one of the flange (14). The opposite flange (15) is shaped so as to form compartments for mating with the downward-facing vertices of the elastomeric blocks (26).