The structure and catalytic properties of Pt and Ni supported on thin films of LaFeO 3 and CaTiO 3 , prepared by atomic layer deposition (ALD), were investigated. X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM) show that reduction at 1073 K causes Pt−Fe intermetallic compound formation for Pt/LaFeO 3 . For Pt/CaTiO 3 , 1073 K reduction induces local decomposition of the CaTiO 3 with migration of Ti to the Pt. Reduced Pt/LaFeO 3 and Pt/CaTiO 3 exhibited CO oxidation activity similar to that for Pt supported on MgAl 2 O 4 but were much less active for propane oxidation and hydrogenation of 1-hexene and toluene. In contrast, Ni/CaTiO 3 behaved similarly to a conventional supported Ni catalyst for the methane steam reforming (MSR) and 1-hexene hydrogenation. There was also no evidence for local decomposition of the perovskite in the vicinity of the Ni particles. The results obtained in this study demonstrate that metal−perovskite interactions that affect reactivity are specific to each component.