The drastic increase in the world’s population leads to a significant surge in the demand for food. Fertilizers play a crucial role to address this escalating need and to ensure food security. The excessive use of traditional or conventional fertilizers leads to environmental problems due to loss of nutrients through leaching, surface runoff, volatilization, and denitrification. Therefore, controlled release fertilizers (CRFs) act as an alternative to conventional fertilizers playing an important role in sustainable agriculture. CRFs act as a viable solution for sustainable agriculture as it improved nutrient efficiency, reduced environmental impacts, lowered application frequency, enhanced plant growth, prevented nutrient loss, and reduced the risk of overfertilization. Different kinds of CRFs have been developed using various physical and chemical methods. Various types of materials are used for coating and encapsulation of fertilizers, whereas the natural biopolymers have gained more attention due to various properties such as biodegradability, biocompatibility, renewability, and being eco-friendly in nature. Agricultural waste biomass-derived cellulose and lignin exhibit a significant role in CRFs. In this chapter, various conventional methods for fertilizer release with a special emphasis on CRFs, method of their preparation, and various polymers used for preparation of CRFs are discussed. Furthermore, the current status of research on hydrogels based on cellulose, lignin, and their modified form for controlled release of fertilizers is discussed. The generalized mechanism and role of sustained release of fertilizers in agriculture are also discussed.