It has widely been observed that the effect of elevating atmospheric CO2 concentrations on rice productivity depends largely on soil N availabilities. However, the responses of ammonia volatilization from flooded paddy soil that is an important pathway of N loss and thus affecting fertilizer N availability to concomitant increases in atmospheric CO2 and temperature has rarely been studied. In this paper, we first report the interactive effect of elevated CO2 and temperature on ammonia volatilization from rice paddy soils applied with urea. Urea labeled with 15N was used to quantitatively estimate the contribution of applied urea-N to total ammonia volatilization. This study was conducted using Temperature Gradient Chambers (TGCs) with two CO2 levels [ambient CO2 (AC), 383 ppmv and elevated CO2 (EC), 645 ppmv] as whole-plot treatment (main treatment) and two temperature levels [ambient temperature (AT), 25.7℃ and elevated temperature (ET), 27.8℃] as split-plot treatments (sub-treatment)