Microfluidic mixing is crucial for achieving rapid and thorough mixing of multiple samples in microscale devices. This review discusses both active and passive mixing strategies. Active mixers use external energy sources like acoustic, dielectrophoretic, electrokinetic, pressure, electrohydrodynamic, thermal, magneto-hydrodynamic, and electrokinetic instability forces to enhance mixing. Passive mixers rely on design features such as increased contact area and contact time through microchannel configurations. Active mixers often use mechanical transducers, such as ultrasonic or electrokinetic devices, to induce mixing. Passive mixers include lamination, intersecting channels, zigzag channels, three-dimensional serpentine structures, embedded barriers, slanted wells, twisted channels, and surface-chemistry technologies. These methods improve mixing efficiency by inducing chaotic advection or enhancing molecular diffusion. The review highlights the advantages and limitations of various mixing techniques, emphasizing the importance of optimizing design parameters for efficient mixing. Active mixers generally offer higher mixing efficiency but may require more complex fabrication. Passive mixers are simpler and more cost-effective but may require longer mixing times. The review concludes that both active and passive mixers are essential for microfluidic applications, with ongoing research focusing on improving mixing performance and reducing device size.Microfluidic mixing is crucial for achieving rapid and thorough mixing of multiple samples in microscale devices. This review discusses both active and passive mixing strategies. Active mixers use external energy sources like acoustic, dielectrophoretic, electrokinetic, pressure, electrohydrodynamic, thermal, magneto-hydrodynamic, and electrokinetic instability forces to enhance mixing. Passive mixers rely on design features such as increased contact area and contact time through microchannel configurations. Active mixers often use mechanical transducers, such as ultrasonic or electrokinetic devices, to induce mixing. Passive mixers include lamination, intersecting channels, zigzag channels, three-dimensional serpentine structures, embedded barriers, slanted wells, twisted channels, and surface-chemistry technologies. These methods improve mixing efficiency by inducing chaotic advection or enhancing molecular diffusion. The review highlights the advantages and limitations of various mixing techniques, emphasizing the importance of optimizing design parameters for efficient mixing. Active mixers generally offer higher mixing efficiency but may require more complex fabrication. Passive mixers are simpler and more cost-effective but may require longer mixing times. The review concludes that both active and passive mixers are essential for microfluidic applications, with ongoing research focusing on improving mixing performance and reducing device size.