This study was conducted to clarify the effect of indentations and baffles formed in a deep microchannel on the mixing performance. Since the fluid flow in a deep microchannel is laminar, the mixing relies on the molecular diffusion, which typically takes several hundreds of seconds even in microscale-channels. Formation of indentations and baffles is expected to be a convenient approach to enhance mixing rate in deep microchannels. Results from both theoretical and experimental investigations demonstrated they induce the secondary flow in the downstream of the intersection and thus enhance mixing. The mixing performance was influenced by their dimensions and the flow rate. The study showed that the flow rate was one of the most important parameters which affect the mixing rate. (C) 2010 Elsevier B.V. All rights reserved.