This paper reports an experimental investigation into the heat transfer response of plastic microcapillary flims (MCFs). The first section presents experimental determination of temperature profiles and heat transfer coefficients for an MCF-based micro-heat exchanger. The next section presents two case studies: the first concerns cooling an electrical load, whereas the second examines heat transfer from an exothermic chemical reaction occurring within the MCF. The results demonstrate that heat transfer transients within MCF heat exchange devices are rapid. These systems provide an effective means of either heating or cooling fluids flowing within an MCF, or for removing heat from a hot surface. (C) 2008 Elsevier Ltd. All rights reserved.