Films formed from saliva on surfaces are important for maintenance of oral health and integrity by serving as barriers against chemical and/or biological agents. OBJECTIVES: The aim of the present study was to investigate the structure of films formed from human whole saliva onto alumina surfaces. METHODS: In situ ellipsometry was used to investigate adsorbed amounts and thickness of the adsorbed layers. Neutron reflectivity and atomic force microscopy (AFM) were used to study the density profile within the adsorbed layer and morphology, respectively, of the adsorbed salivary film onto alumina (Al2O3). RESULTS: The results show that saliva adsorbed rapidly on alumina. First a thin and dense layer covered the surfaces. With time, a thicker and diffuser layer was developed. The film morphology described a uniformly covering dense layer and a second outer layer containing polydisperse adsorbed macromolecules or aggregates. CONCLUSION: The film was found to be composed of two layers: an inner and dense thin region, that forms a uniform layer, and an outer, more diffuse and thicker region that protrudes towards the bulk of the solution. This study was supported by research grants from the Knowledge Foundation, Malmö University, The Swedish Dental Society, The Swedish Patent Revenue Fund for Research in Preventive Dentistry, The Swedish Research Council and Uppsala University. We are grateful also to the Institute Laue Langevin, Grenoble for an allocation of neutron beam time.