Three designs of passive microfluidic mixers (fabricated using Micralyne Protolyne technology on a glass substrate) are studied and compared to a basic straight channel diffusion mixer. The designs are analyzed under continuous and pulsating flow conditions using numerical and experimental tools; specifically finite element analysis and particle image velocimetry. Testing and analysis are performed at pressures that can be generated using reciprocating membrane micropumps integrated into a Micro Total Analysis System. It is determined that one of the proposed mixer concepts outperforms all of the other designs considered and enhanced mixing is achieved under pulsating flow. Performance is judged based on criteria that describes the amount of mixing performed, the concentration uniformity at the outlet of the mixer, and the net flow rate. Recommendations are made on how to improve the overall performance of the passive micromixers.