Electrokinetic analysis is a family of techniques for estimating the charge on solid surfaces, macroscopic particles, colloidal species, and macromolecular aggregates. Charges on surfaces are critical to the behavior of colloids, coatings, films, fibers, and many other materials in a variety of application areas. In addition to estimating the charge, elctrokinetic analysis provides the means for measuring how the surrounding medium and imposed electric fields interact with extended flat surfaces. Channels, pores, particles, and molecular aggregates to produce motion. Such motion has found wide use as a means for separating complex mixtures into their components. This section will present how measurements are made, some theoretical underpinnings, and examples of the instrumentation used for making measurements.