Abstract: A biosensor is an analytical device that responds in a direct. reversible. continuous. rapid. and accurate (precise) manner to changes in the concentration of chemical or biochemical species in an untreated sample. It may consist of a sensing microzone where a chemical or biochemical reaction (and. occasionally. a separation process) takes place. which is connected or integrated with an optical. electric. thermal. or mass transducer. Biosensor technology has emerged as a dynamic field of biotechnology with new methods of detecting specific chemicals at analytically useful levels [1, 2]. Its impact has been largely due to the advances made in bioelectrochemistry. microelectronics. and micro-optic technology. Biosensor research attracts scientists from far-ranging fields such as pharmacology. biochemistry. protein chemistry. material science. environmental science. electronics. and physics [3]. This coherent multidisciplinary approach is vital for the successful introduction of biosensors in new and existing fields. Biosensors have found applications in various analytical fields [4-18] including bioprocess control, biomedical analysis, environmental monitoring and control, food pharmaceutical or petrochemical analysis, and even defense. For instance, glucose biosensors are used to determine glucose in analytical [19] and clinical laboratories [20], monitor glucose levels in fermentation reactors [21, 22], estimate glucose in the food industry [23], and in pharmaceutical processes [24]. The performance and usefulness of these types of biosensors are often dictated by the immobilization methods and the immobilization matrixes employed for the deposition of the enzyme layer. For example, the sensor lifetime, its dynamic range, sensitivity, selectivity, response time, stability, and susceptibility to interferents are some of the operational parameters affected by the enzyme immobilization procedure and the type of support materials used for the biosensor fabrication. In this paper, we concisely review the theoretical aspects of the biosensor, the methods of enzyme immobilization, and the polymers as enzyme immobilization matrixes in the enzyme biosensors in recent publications.