Man made fertilizers have come to stay in the 20 century for increasing the output of agricultural production and to meet the ever increasing demand of human population, which has been further accentuated by the limited availability of additional fertile farm land. The pathway of productivity improvement followed so far has, however, been accompanied by an exponential increase in the consumption of nonrenewable form of energy. Manufacture of chemical fertilizers is heavily dependent on energy derived from fossil, which is getting depleted at a very fast rate. On the contrary, biofertilizers require much less energy and are dependent on energy from renewable sources such as products of photosynthesis and organic matter in the soil. The nutrients provided by biofertilizers to the agroecosystem do not pose any health risk to human which is being seriously apprehended by the use of chemical synthetic fertilizers. With almost twice the quantity of plant nutrients being removed from soil than added through fertilizers, the growing nutrient imbalance poses a major threat to sustain soil health and crop productivity. Huge investment will be needed to install factories to meet the growing demand of chemical fertilizers. The fertilizers so produced is not only high price but also the factories themselves have and adverse effect on the environment. Chemical fertilizers are not only costly but growing awareness of environment pollution and limitations of nonrenewable resource may introduce additional constraints. Since the ancient time, mankind has taken advantage of microorganism appreciating their beneficial role in living system. In the later half of last century, their role in agriculture has been recognized as biofertilizers.