Nitrogen is one of essential nutrients in rice production. Although nitrogen supply increased productivity, nitrogen utilization efficiency was very low in rice production. Some researchers revealed that nearly two-fifths of nitrogen input was lost in different pathways. Excessive use of nitrogen fertilizer not only caused waste of resources but also brought harmful impacts on eco-environment, such as greenhouse effect and pollution to water body and soil. Rice paddies are regarded as one of major CH₄ emission sources with annual estimates about 31 to 112 Tg, accounting for 5%-19% of global total CH₄ emissions. CH₄ emission was promoted by application of fresh organic fertilizer and significantly reduced by biogas fertilizer after fermentation treatment in rice paddies. Effects of chemical nitrogen fertilizer on CH₄ emission from rice paddies were complicated, which were controlled by soil C/N ratio, fertilizer type, fertilization amount and mode, etc. Fertilization affected CH₄ emission through influencing soil physicochemical properties, soil microbial community (methanogens and methanotrophs) and plant growth (e.g. development of aerenchyma, formation of root exudates). Controlled-release nitrogen fertilizer (CRNF), as eco-friendly fertilizer, is able to delay nitrogen release, provide a synchronous N supply for plant, thus reduce the accumulation of inorganic N in soil and the risk of N losses. Fewer reports are available regarding the effect of controlled-release N fertilizer on CH₄ emission in rice paddies. Genetic transformation in rice has achieved rapid development since the first transgenic modification in 1988. Genes containing traits such as resistant to insects, diseases, and tolerant to herbicides, drought and salt have been effectively transferred into different rice varieties. Transgenic rice brought higher yield with less labor intensity, cost and use of pesticides and environmental pollution. However, it is still under argument about the safety of transgenic rice on eco-environment and human health under commercial cultivation. A pot experiment with rice cultivars was conducted to investigate the effect of nitrogen fertilizers on CH₄ emission from a paddy soil under greenhouse conditions. The experiment was designed with two fertilizer types, i.e. urea and controlled-release nitrogen fertilizer (CRNF), and two rice cultivars, i.e. herbicide-resistant transgenic rice (japonica line B2) and its parent conventional rice (japonica cv Xiushui 63), and performed at the Station of Agricultural Meteorology, Nanjing University of Information Science and Technology, Nanjing, China. CH₄ emission was determined by the closed chamber method at 10-day interval during rice growing period in a loamy clay paddy soil. The results indicated that, compared with control (urea), CRNF supply increased tiller number, plant height, biomass and yield in rice. CH₄ fluxes gradually increased from 22 d after transplanting, then reached the main peak at reproductive phase (62-92 d after transplanting), and sharply decreased until rice harvest. In comparison with control (urea), one-time basal application of CRNF significantly decreased CH₄ emission from the paddy soil. The total CH₄ emission was significantly lower from the transgenic rice cultivar than the conventional rice cultivar. It is suggested that one-time basal application of CRNF and planting herbicide-resistant transgenic rice are helpful in mitigating CH₄ emission from the paddy soil.