The objective of this chapter is to introduce the electrophoresis. Electrophoresis is the method of separation of macromolecules of biological fluids (e.g. serum, urine, CSF, etc.) by the movement of charged particles through an electrolyte when subjected to an electric field. As such, it is one of the most widely-used techniques in biochemistry and molecular biology. Principles of electrophoresis, types of electrophoresis, and uses of electrophoresis are also discussed in this chapter. It is widely used for separation of proteins in biological fluids in various conditions like identification of different types of Hb in hemoglobinopathies, in chronic infections, cirrhosis of liver, nephritic syndrome, and multiple myeloma (Bence Jone’s protein).