There is an urgent need to develop superior nitrogen -effi cient rice varieties because of poor fertilizer nitrogen use effi ciency (NUE), associated economic and environmental concerns, and the lack of adoption of improved nitrogen management practices. Genotypic variation in NUE has been reported for rice in many studies. The physiological mechanisms underlying both nitrogen uptake effi ciency and utilization effi ciency are fairly well understood. Plant traits that are closely associated with NUE have been identifi ed. In general, there is a positive relationship between grain yield and NUE, suggesting that it is possible to develop rice varieties with both high grain yield and high NUE. An empirical breeding method can be used for developing nitrogeneffi cient varieties using existing genotypic variation in NUE. However, for signifi cant improvement in NUE, new breeding techniques such as the development of F 1 hybrids, marker -aided selection, transformation, and genetic engineering should be considered.