Yield functions of de-excitation gamma rays following the Coulomb excitation of 191Ir and 193Ir by oxygen ions have been measured. Reduced E2 and M1 transition probabilities were obtained for transitions among the low-lying levels: 3 2+ (ground state), 1 2+, 3 2+', 5 2+, 7 2+. The results are compared with the predictions of the core excitation model. © 1969.