Bio-fertilizer is a substance used to increase the fertility of the soil. It contains micro-organisms which help the soil to gain its nutrient back and make the soil available for cultivation. Bio-fertilizer don’t make any kind of pollution, so it is not a threat to use them in the place of the chemical fertilizers which causes a lot of pollution to the environment. Plants nutrients are essential for the production of crops and healthy food for the world’s ever-increasing population. Soil management strategies today are mainly dependent on inorganic chemical-based fertilizers, which cause a serious threat to human health and the environment. Bio-fertilizer has been identified as an alternative for increasing soil fertility and crop production in sustainable farming. The exploitation of beneficial microbes as bio-fertilizers has become of paramount importance in the agricultural sector due to their potential role in food safety and sustainable crop production. Bio-fertilizer can be an important component of integrated nutrients management. Microorganisms that are commonly used as bio-fertilizer components include; nitrogen fixers (N-fixer), potassium and phosphorus solubilizers, growth-promoting rhizobacteria (PGPR), endo and ectomycorrhizal fungi, cyanobacteria and other useful microscopic organisms. The use of bio-fertilizers leads to improved nutrients and water uptake, plant growth, and plant tolerance to abiotic and biotic factors. These potential biological fertilizers would play a key role in the productivity and sustainability of soil and also in protecting the environment as eco-friendly and cost-effective inputs for the farmers.