Greenhouse-gas emission factors are widely used to estimate emissions arising from a defined unit of a specific activity. Such estimates are used both for international reporting to the United Nations Framework Convention on Climate Change (UNFCCC) and for myriad national and sub-national reporting purposes (for example, European Union Emissions Trading Scheme; EU ETS). As with the other so-called "Kyoto protocol GHGs", the Intergovernmental Panel on Climate Change (IPCC) provides a methodology for national and sub-national estimation of N₂O emissions, based on the sector from which the emissions arise. The objective of this study was to develop a integrated emission factor to estimate the direct N₂O emission from an agricultural field cultivated with the red pepper, soy bean, spring cabbage, autumn cabbage and potato in 2010∼2012. Emission factor of N₂O calculated using accumulated N₂O emission, N fertilization rate, and background N₂O emission over three year experiment was 0.00596±0.001337 kg N₂O-N (N kg)-1. More extensive studies need to be conducted to develop N₂O emission factors for other upland crops in the various regions of Korea because N₂O emission is influenced by many factors including climate characteristics, soil properties, and agricultural practices.