The objective of this study is to elucidate the catalytic performance of hexaaluminate catalysts incorporating Cu and Ir simultaneously during the decomposition of an ammonium dinitramide (ADN)-based liquid propellant. Pellet-type catalysts were prepared and their chemico-physical properties were characterized by N₂ adsorption, XRD, and XRF. It was confirmed that Cu and Ir atoms are well incorporated inside the hexaaluminate matrix of the Cu(x)Ir(10-x)-hexaaluminate catalysts and the content of Ir incorporated into hexaaluminte matrix was in the range of 2.5-8.2 wt%. The Cu(7)Ir(3)-hexaaluminate catalyst showed excellent activity in decomposition of ADN-based liquid monopropellant. The activity of the Cu(7)Ir(3)-hexaaluminate catalyst was much higher than that of the Cu(7)Ir(3)/hexaaluminate-imp catalyst prepared by impregnation of Cu and Ir onto the hexaaluminate pellet surface. This is attributed to the Cu and Ir being well incorporated in the hexaaluminate matrix and the dispersion of the Cu and Ir being greater in the Cu(7)Ir(3)-hexaaluminate than in the Cu(7)Ir(3)/hexaaluminate-imp.