Publisher Summary This chapter discusses the processing properties and applications of micro-/nano-fibers by electrospinning technology. Electrospinning is a fiber-spinning technology used to produce long, three-dimensional, ultrafine fibers with diameters in the range of a few nanometers to a few microns (more typically 100 nm to 1 micron) and lengths up to kilometers. When used in products, the unique properties of nano-fibers are utilized, such as extraordinarily high surface area per unit mass, very high porosity, tunable pore size, tunable surface properties, layer thinness, high permeability, low basic weight, ability to retain electrostatic charges and cost effectiveness, among others. These fibers are used not only in clothing but also in hygienic products, in medical and automotive applications, in geo-textiles and in other applications. Traditional methods for polymer fiber production include melt spinning, dry spinning, wet spinning and gel-state spinning. These methods rely on mechanical forces to produce fibers by extruding extruding a polymer melt or solution through a spinneret and subsequently drawing the resulting filaments as they solidify or coagulate.