The fabrication of microfluidic devices is of great importance in many fields of bioanalytical science; where a small quantity of a sample is available, enhanced resolution and sensitivity in separation is needed, and increased functional integration is desired (medical, chemical, and biochemical analysis, microchemistry, etc.). Even though the first microfluidic devices were fabricated on silicon (Si) and glass, the need for easy fabrication and forming, low cost and disposability, the wide range of properties (optical, chemical, and mechanical) and biocompatibility has shifted the attention on polymeric materials. The most frequently used polymers include poly(methyl methacrylate) (PMMA), polycarbonate (PC), cyclic olefin materials [e.g., cyclic olefin copolymer (COC) and cyclic olefin polymer (COP)], SU-8, and poly(dimethylsiloxane) (PDMS). However, the surface of polymers does not always have the desired properties for specific applications. Thus, polymer surface modification is needed. Plasma processing of polymers has attracted attention because of its unique characteristic advantages, such as dry character, no waste production, speed of processing, and many more. In addition, plasmas have been proposed not only for modification, but also for fabrication of microfluidics. To cover this emerging field, we present below an introduction to fabrication and modification of polymeric microfluidics using plasma processing.