Microfluidic devices offer distinct benefits in developing effective drug carrier particles, systems for cell-devoid protein synthesis, and quick methods for direct drug screening. Compared to traditional approaches, microfluidic technology produces extremely stable, homogeneous, monodispersed particles with better encapsulation efficiency by effectively managing the manufactured chip’s geometries and the multiphase fluids’ flow rates. Microfluidic three-dimensional platforms imitate in vivo cell systems in a straightforward, cost-effective way that allows for high-throughput and integrated drug screening at the cell, organ, and whole-body levels, in contrast to two-dimensional cell culture methods and in vivo animal models. Microscale chips with channels and chambers can be created by processing various materials. Such platforms can be produced with a wide range of techniques to achieve the required size, shape, and geometry. Microfluidic chips can be utilized independently or in conjunction with other devices for nanoparticles, drug encapsulation, delivery, targeting, cell analysis, diagnostics, and cell culture. An efficient, portable microfluidic system can be used for sample pretreatment, separation, dilution, mixing, chemical reaction, detection, and product harvesting. These methods can improve analytical speed and efficiency while simultaneously using fewer samples or reagents in disease diagnosis. The development of microfluidic devices is covered in this chapter, along with the latest developments in their use in the wide range of therapeutic administration and medical diagnostic applications.