This paper gives further evidence of successful use of energy-filtering transmission elctron microscopy (EFTEM) for studying the polymer morphology of unstained samples. The method presents numerous advantages compared to traditional chemical staining methods using toxically staining agents such as osmium and ruthenium tetraoxide. For this purpose an EFTEM LEO912 equipped with an omega filter was used to produce conventional brightfield unscattered images and inelastic filtered images of high impact polystyrene ultramicrotomed samples. It was shown that morphology details observed in unstained samples are equivalent in quality contrast to those stained with osmium tetraoxide.