Low-voltage transmission electron microscopy (LV-TEM) was applied to obtain images of the phase structure of selected polymer blends without any prior staining. The instrument used (LVTEM-5, working at 5 kV) is of a novel construction combining visual-light and electronmicroscopical techniques, resulting in an enhanced efficiency of light transport to the eye and facilitating CCD imaging. Results were compared wi th LV-STEM at 25 kV. Phase structure of polycarbonate/poly( styrene-co-acrylonitrile) (PC/SAN), polystyrene/polypropylene (PS/PP), and polyethylene/polypropylene blends (PE/PP, ADFLEX) were selected to demonstrate the above techniques. The difference in density between the individual components of polymer blends was found to be the reason for the obtained image contrast. Differences less than 0.04 g/cm(3) can be traced with this technique. (C) 2000 Elsevier Science Ltd. All rights reserved.