In this review article the basic principle of separation process during Micellar electro kinetic chromatography (MEKC) are described. The separation mechanism in MEKC is based on differences in equilibrium between an aqueous Phase and micellar Phase. These Phases are moving different velocities, due to a combination of electrophoresis & electro osmosis. It is a useful branch of capillary electrophoresis (CE) that utilizes surfactant above critical micelle concentration (CMC) as pseudo-stationary phase. MEKC can be employed to separate both charged and neutral molecules, individually or simultaneously, including chiral compounds. MEKC benefits from high peak efficiency due to electro-osmotic flow (EOF) in the separation capillary, compounded with large variety of synthetic surfactants, organic modifiers, temperature and variable separation voltage has made MEKC the method of choice for separation scientists. In this review, we present the introduction of CE, fundamentals of surfactant chemistry as it relates to MEKC, separation principles in MEKC including equations involved in calculating separation parameters (capacity factor, resolution etc.).