This paper presents a new type of passive microfluidic mixer called the "H-micromixer". This type of passive micromixer is based on the splitting and recombination (SAR) process, meaning that the two fluids to be mixed are split and recombined to optimize the diffusion process. The paper also describes an experimental investigation of the mixing process in three different geometries: T-micromixer, O-micromixer and H-micromixer. The laminar flow regime (0.08 < Re < 4.16) was considered during tests and image-based techniques were used to evaluate mixing efficiency. At all tested flow rates, experimental data show that the H-micromixer is more efficient than the other tested microdevices. The H-micromixer's efficiency is very high due to the SAR process: specifically, efficiency up to 98% can be achieved at Re=0.083. Crown Copyright (c) 2012 Published by Elsevier Ltd. All rights reserved.