X-ray photoelectron spectroscopy (XPS) is ideally suited to the study of copper-based biocidal films. This application note provides an insight into the use of XPS in understanding the surface chemistry, elemental composition, and mechanisms of copper-based biocidal films. By employing XPS, it is possible to gain valuable insights into the oxidation states of copper, the presence of contaminants, and the chemical bonding at the film surface. This knowledge contributes to the optimization of film design and performance, ultimately leading to enhanced antimicrobial properties and improved hygiene.