The review is devoted to the patents literature development in the field of biosensors during the last 20 years. Aspects related on the polymeric gels used into sensor devices, as well as some general characteristics to the analyte biosensor based on polymeric gels, they are presented. The scientific publications in connection with the presented data are cited. It is also underlined that the entire area of chemical biosensors is much too larger than the electrochemical sensors discussed here. Optical, thermal, and surface acoustic wave sensors, for example, are all exciting research areas that complete the field of electrochemical sensors.