Laminar flow and mixing of a Newtonian fluid are characterized in a four-element Koch-Glitsch SMX static mixer. The computational analysis on a fine, unstructured mesh containing more than 3.5 million tetrahedral elements led to high-resolution numerical data for velocity and pressure. Computed pressure drops agreed excellently with those in the literature. The flow in this static mixer is essentially independent of the flow rate up to Re = 1, thereby causing the flow characteristics to deviate substantially from those observed when Re < 1. Furthermore, mixing behavior is examined using Lagrangian particle tracking simulations, as well as statistical methods to facilitate comparisons with experimental data. The mixing rate calculated from the simulations agreed closely with experimentally measured values. Both exponential decrease in the variation coefficient as a function of downstream length and the evolution of a self-similar mixing structure are both evidence of chaotic mixing in the SMX mixer.