Nanotechnology-based sensing has gained huge attention and fetched broad-spectrum applications in the food and agriculture sectors. Nano-biosensors are small, portable research tools that are used to determine the presence and level of harmful substances in soil, wastewater, and agricultural products. They are capable of producing definite systematic data by employing a recognition component of biological origin which is joined to a signal transformation unit. The unique properties of nano-materials are responsible for high selectivity, specificity, linearity, accuracy and stability of nano-biosensors.