One hectare of primary forest in Central Kalimantan was enumerated and all trees 10 cm dbh tagged and identified to species as far as possible. Two informants, regarded as the most knowledgeable on forest trees by the local community, supplied the vernacular names for the trees. The study found that only 12% of vernacular names given by one informant and 22% by the second could be equated consistently to taxa. Of these taxa 77% were given the same vernacular name by both informants and the remaining 23% had an obvious common origin (cognate). Many of these taxa were distinctive or had a use to the informants. The results have important implications for the conversion of vernacular names to scientific names by anyone carrying out inventory work in Kalimantan.