This book gives an insight about isolation, characterization and Nitrogen fixing efficiency of Azotobacter strains and their effect on finger millet as well as soil quality. Azotobacter has been reported to have sufficient demand of carbon substrate for energy requirement, major and micro nutrients optimum pH, temperature, aeration, etc. for growth, multiplication and survival in a particular medium. The grain and stover yields were increased significantly which shows the importance of Azotobacter in substitution of fertilizer nitrogen to some extent. The inoculation of Azotobacter and graded levels of urea both boost plant growth and yields however, inoculation is cost effective, eco-friendly and renewable source of nitrogen to supplement fertilizer nitrogen for crop demand.