A novel passive micromixer was developed for microchemical applications. The flow path of the proposed micromixer was characterized by the combination of a square-wave structure and periodic cubic grooves. This micromixer can be easily fabricated by conventional mechanical processing. The simulation on computational fluid dynamics showed that the square-wave structure caused laminar recirculation, and the cubic grooves induced flow stretching. These two chaotic advection mechanisms jointly contributed to the 3D periodic perturbation, resulting in considerably enhanced mixing over a wide range of the Reynolds number. The structural parameters of the micromixer were optimized in the simulation, with groove location taken as the key variable. The overall performance, including the mixing quality and pressure drop, of the optimum micromixer was experimentally evaluated and compared with those of five commercial micromixers presented in the literature. Experimental results demonstrated the superiority of the micromixer proposed in the current study. (C) 2011 Elsevier B.V. All rights reserved.