Electronic Nose is one of the most advance device in the field of sensor technology. It is responsible for the automated detection and classification of gases, odors and vapors. This paper reviews the three components of Electronic Nose i.e. sample handling, detection system, data processing system. It outlines the range of sensors their principles, advantages and disadvantages. It describe the data processing through pattern recognition process. It also outlines the enormous benefits of Electronic Nose in the field of food control, clinical diagnosis, cosmetics, environmental factors, garbage control and detection of plant diseases.