The application of light microscopy to the study of protein-surface interactions is described with several examples showing its versatility . Extensive use is made of image analysis algorithms to extract quantitative information from the digital images and it is shown how this can shed light on the processes taking place on the surface . Amongst the surfaces investigated are siloxane films on silicon wafers, glucose oxidase/poly(ethyleneglycol) films cast onto glass slides and glucose oxidase entrapped in electropolymerised poly(phenyleneoxide) films on platinum . Parameters that can be measured include : surface loading, surface heterogeneity, distribution of enzyme activity, surface mobility and film porosity . Both reflected light and fluorescence microscopy were used to characterise the surfaces and it was concluded that not only does light microscopy offer a powerful tool for the characterisation of surfaces but it may also provide an interface between bioelectronic materials and conventional computing machinery .