This paper presents the result of a large thermal comfort survey conducted using 1520 Thai volunteers from different climatic regions of Thailand. The survey was conducted using different types of air-conditioned buildings from the private and public sectors. Apart from common thermal comfort factors such as air dry bulb temperature, relative humidity and air velocity, two non -quantifiable factors were considered. These are the acclimatization to the use of air conditioner at home and the education level, i.e., post graduate, graduate and scholar. A general database for thermal comfort studies in Thailand was created, and different thermal comfort standards were developed for the three climatic regions of Thailand. Twenty six degree Celsius and 50-60% relative humidity could be used as a comfortable environment condition for the whole country. The data was then used to generalize an earlier concept we developed for setting thermal comfort standard using data from non air-conditioned buildings. (c) 2004 Elsevier Ltd. All rights reserved.