Nitrous oxide (N 2 O) emissions from the soil surface of five different forest types in Thailand were measured using the closed chamber method. Soil samples were also taken to study the N 2 O production pathways. The monthly average emissions (AESD, n ¼ 12) of N 2 O from dry evergreen forest (DEF), hill evergreen forest (HEF), moist evergreen forest (MEF), mixed deciduous forest (MDF) and acacia reforestation (ARF) were 13.0 AE 8.2, 5.7 AE 7.1, 1.2 AE 12.1, 7.3 AE 8.5 and 16.7 AE 9.2 mg N m À2 h
À1, respectively. Large seasonal variations in fluxes were observed. Emission was relatively higher during the wet season than during the dry season, indicating that soil moisture and denitrification were probably the main controlling factors. Net N 2 O uptake was also observed occasionally. Laboratory studies were conducted to further investigate the influence of moisture and the N 2 O production pathways. Production rates at 30% water holding capacity (WHC) were 3.9 AE 0.2, 0.5 AE 0.06 and 0.87 AE 0.01 ng N 2 O-nitrogen (N) g-dw À1 day À1 in DEF, HEF and MEF respectively. At 60% WHC, N 2 O production rates in DEF, HEF and MEF soils increased by factors of 68, 9 and 502, respectively. Denitrification was found to be the main N 2 O production pathway in these soils except in MEF.