Bio- and nano-fertilizers are one of the most important tools in modern agriculture and agri-food as well as a driving economic force in the near future. Also, bio- and nano-fertilizers also play an important role as promising methods for increasing use efficiency of different water and land resources, reducing environmental pollutions as well. So, environment friendly biotechnological approaches may offer alternatives to chemical fertilizers. Phosphurus, K and Zn solubilizer microbes are the most important microbial traits in soil biogeochemical cycles and plant growth promotion. The biosynthesis of nanomaterials using bacteria, algae, yeast, fungi, actinomycetes and plants has led to a new area of research for the formation of inorganic nanoparticles as eco-friendly fertilizers. Now, use of nanofertilizers in plant nutrition is one of the major roles of nanotechnology in agriculture and soil sciences. Thus, the application of biosynthesized nanoparticles in agricultural sector may lead to sustainable development. Hence, this leads to sustainable agriculture through putting less inputs and generating less wastes, minimizing nutrient losses, and release nutrients at a proper rate for plant demand comparing with conventional farming. There is very slight difference between bio- and nano-fertilizers depending on their mechanisms in the soil and plant, application methods, effective rates of addition as well as their impact on the environment. However, both nano-and bio-fertilizers and their interaction are needed further studies. Therefore, this review will focus on the new insights and a comparison between both nano- and bio-fertilizers.