Nitrous oxide (N 2 O) emission from flooded rice paddy fields was continuously measured by the closed chamber method at an experimental plot in Thailand for a whole cultivation period. To characterize the N 2 O emission with regard to the denitrification N loss, the C 2 H 2 inhibition method was applied. Flood water on the soil greatly suppressed the N 2 O emission. The N 2 O emission was mitigated considerably by even a thin film of the flood water. The overall average N 2 O emissions under flood conditions for one crop season (83 days) at the control site and the C 2 H 2 treated site were 10.3 and 11.8 lg N m -2 h -1 , respectively. The N 2 O emission from the C 2 H 2 treated site was consistently higher than that from the control site and the N 2 O emission from both sites followed the same diurnal and seasonal variation pattern, indicating the effect of denitrification inhibition by the supplied C 2 H 2 . The N 2 O emission enhanced along with temperature increase when NO 3 -N concentration in the soil water was above 0.4 mg N l -1 and soil temperature was above 24°C, suggesting specific temperature influence over the emission.The increase in NO 3 -N concentration and temperature in the soil affected only the N 2 O emission while the difference in the emission at the C 2 H 2 treated site and the control site was not so much affected. It was suggested that most of the actively produced N 2 O under higher NO 3 -N concentration and temperature would likely to quickly emit to the atmosphere rather than to undergo further reduction to N 2 .