Global food security is largely dependent on agriculture, and the Green Revolution was a turning point in raising crop output to keep up with population growth. Despite being successful in increasing yields, conventional agricultural practices and chemical fertilizers have had detrimental effects on the environment, including soil deterioration, water pollution, and biodiversity loss. Innovations in fertilizer technology, particularly biofertilizers, offer a sustainable solution by enhancing nutrient availability, improving soil health and promoting eco-friendly farming practices. Biofertilizers comprise living microorganisms that fix atmospheric nitrogen, dissolve phosphorus, and promote plant development via organic biological processes. They play a critical role in sustainable agriculture by decreasing chemical dependency, improving crop yield and maintaining ecological balance. This chapter discusses the types, mechanisms, applications and benefits of biofertilizers, focusing on nitrogen-fixing and phosphate-solubilizing microorganisms and highlights their importance in ensuring sustainable agricultural growth.