Colour and opacity are two parameters very important to describe optical properties of edible films. The aim of this study was to investigate the effect of fat emulsion on the optical properties of whey films. They were prepared from 10% whey protein isolate and glycerol at 50% (w/w) as a plasticizer of aqueous solutions. The mixtures were heated in water bath at 80ºC for 30 min at 50 rpm. 10% emulsion of rapeseed oil was added to film-forming solutions at four levels of 10, 20, 30, and 40%. Colour was analysed in the L*a*b* system with parameters (total colour difference, colour saturation and saturation index). Opacity was analysed at a wavelength of 600 nm. Modification of composition of film forming solutions with addition of fat emulsion caused that all films obtained were matt and opaque. Changes in colour of whey-emulsion film were observed. The increasing opacity was shown when the fat emulsion content increased in film-forming solutions.