We describe a novel design for a micromixer that generates vortical flow in a rectangular microchannel with tangentially aligned inlet channels. The mixing performance of the proposed vortex T-mixer with non-aligned inputs is compared to a simple T-mixer as a function of Reynolds number. The mixer generates the formation of mixing-inducing flows even at low Reynolds numbers as compared to a simple T-mixer. The vortex initially formed at the inlet of a rectangular microchannel increases the interfacial area of the fluid streams by stretching. The proposed vortex mixer is easy to fabricate and offers a tunable control for the generation of vortical flow based on Reynolds number. (C) 2011 Elsevier B.V. All rights reserved.