Résumé : The cross section for the 18F(p,α) 15O reaction has been obtained in reverse kinematics (18F beam on CH2 target) between 550 and 740 keV above threshold, i.e. in a region of astrophysical interest. The reaction yield is dominated by a wide resonant state whose spin, parity, total width and partial widths were deduced from the analysis of the α-particle and elastic proton data.