The rotational transitions J=1→2 and 2→3 were measured for 107Ag 19F and 109Ag 19F by microwave absorption. These spectra allowed the determination of the Dunham-coefficients Y01, Y11, Y21, and Y02 and from these the potential coefficients a0 and a1 and internuclear distance re were derived. For 63Cu 19F and 65Cu 19F the hyperfine structure was observed in the J=0→1 and 1→2 rotational spectra. In addition to the Dunham coefficients the quadrupole coupling constants, e q Q, and spin-rotation coupling constant, c, for the Cu nucleus were obtained. Stark effect mea-surements on both AgF and CuF resulted in the determination of the electric dipole moment for the ground vibrational state.