Electroanalytical techniques are currently gaining popularity in the area of biochemical analysis. There are several reasons for this growth. Electrochemical techniques provide both excellent detection limits with wide dynamic range. These methods are typically readily amenable to miniaturization. This leads to being able to use very small sample volumes. In vivo analysis is also possible. Finally, electrochemical techniques are generally very selective and when not selective enough can easily be coupled to even more selective techniques such as liquid chromatography or immunoassay. In this chapter, the basic concepts underlying electroanalytical methods of bioanalysis will be described. How these techniques can be used in bioanalytical chemistry will be illustrated. In addition, the interrelationship of the various electroanalytical techniques will be discussed.