There are few palaeoenvironmental data from the Indo-Chinese peninsula that document environmental and climatic conditions prior to the Holocene. This study of pollen and spores from a small peat-swamp in north-east Thailand provides a record of vegetation change covering ca. 40,000 years B.P. (Before Present). These data indicate that the region supported a Fagaceous-Coniferous forest, similar to contemporary vegetation described from south-west China. Climatic conditions were cooler and probably drier than present day climates in Thailand. Levels of biomass burning are relatively high throughout this period. Tropical broad-leaf deciduous forest becomes dominant at the Pleistocene/Holocene boundary with the fragmentation of Fagaceous-Coniferous forest in response to increased temperatures.