Rice the major food crop of half of the world’s population, requires large amount of mineral nutrients including C and N for their growth, development and production. Rice crops remove around 16–17 kg N for the production of each ton of paddy. Most of the rice soils of the world are deficient in N, so, fertilizer N applications are required to meet its demand. Generally, urea is applied as the N source for rice production. But the efficiency of added urea-N is very low, due to denitrification, NH3 volatilization and leaching. In addition to these, regular depletion of this inorganic fertilizer causes environmental hazards which are of great concern to the soil and environmentalists around the world. Therefore, alternate sources of N should be applied to minimize these problems if possible. Azolla and cyanobacteria biofertilizer are considered as a potential source of nitrogen and or nutrient supply to rice plant under water logged condition. This book Mineralization and Availability of Azolla and Cyanobacteria nutrient biomass in Rice soil contains the valuable information about the beneficiary effects of Azolla and Cyanobacteria biofertilizer to increase the production of Rice.