Biosensor, an analytical tool, is used to get analytical data using biological samples. These are consist of a biological recognition unit and transducer. The biological recognition unit interacts with enzymes and antibodies, whereas the transducer twists the property of bio-elements like enzymes and antibodies into an electrical signal. Biosensors have variety of applications such as Medicine, food toxicity detection, Agriculture and Biodefense. Biosensors are easy to operate, gives quick results, portable and available at low-price which led to the rapid adoption of Biosensors in fields like medicine, agriculture and environment monitoring. Biosensors have different types such as electrochemical, light addressable potentiometric, resonant mirror, and surface plasmon resonance.