The present work is concerned with the relationship between the interfacial reaction and adhesion at PVD TiO2 film-metal (titanium or aluminium) interfaces as a function of substrate temperature using Auger electron spectroscopy, scanning electron microscopy and the scratch adhesion test. TiO2 films were prepared by reactive r.f. magnetron sputtering on titanium and aluminium at substrate temperatures ranging from 313 to 523 K. Scanning electron microscopy suggested that hardly any compound formation occurred but an interdiffusion layer was formed at the TiO2-Ti interface. In contrast, Auger electron spectroscopy depth profiling and scanning electron microscopy revealed the formation of aluminium oxide at the TiO2-Al interface. The fracture mode of TiO2 films on titanium changed predominantly from chipping below 388 K to cohesive type above 438 K. In contrast, the TiO2 filMS on aluminium fractured in a fully adhesive manner only at substrate temperatures higher than 438 K. Variations in adhesion of the TiO2 films on titanium and aluminium could be explained by the effect of substrate temperature on the interfacial reaction.