Numerical investigations pertaining to heat transfer enhancement of a plate-fin heat exchanger using two rows of winglet type vortex generators (VG) have been performed in this work. Five different strategic placements of the VG, namely, common-flow up in series (CFU-CFU), common-flow down in series (CFD-CFD), combined (CFD-CFU), inline rows of winglet (IRW) and staggered rows of winglet (SRW), were considered. Performance parameters in terms of Nusselt number and quality factor were evaluated from the velocity and temperature data obtained from the solutions of full Navier-Stokes and energy equations. The Reynolds number was varied in the range of 250-1580. Results show that amongst the different types of arrangements of the VG, performance of CFU-CFU configuration is best in terms of heat transfer as well as quality factor. (C) 2012 Elsevier Ltd. All rights reserved.