Biotechnology is the rapidly growing segment in biological sciences. It has diversified applications in sustainable agriculture. The review deals with microbes in biotechnology and their diversified applications in agriculture as biofertilizers, bio-pesticides, bio-herbicides, bioinsecticides, fungal based bioinsecticides and viral based bioinsecticides. Further, precise descriptions have been made on Microbiology Ecology Biotechnology and Sustainable agriculture in the later part of the review. Finally, a brief highlight has been given on the role of Microbial Biotechnology on Environmental Health.