The research examinies a kind of drums called Klong Kon Yao, which is the most essential drum of the Tai people in northern Thailand. Two names are designated to this drum: (1) Klong Kon Yao and (2) Klong Puje. The reearch findings affirm that this drum should be named Klong Kon Yao whereas the name Puje is used only in Chiangmai area. The reason and the history of the naming Puje is still unable to be determined. The drum is found to be from 1.2 meters to 3 meters in height. The drums are played together in a drum ensemble, which is comprised of one drum and three flat gongs. The interval of each gong is fourth or fifth apart. The klong kon yao ensemble is found to accompany auspicious festivals such as Poi Sang Long festival, Ending of the Lent festival. It is also used to accompany several kinds of dances such as Fon Nok, Fon To, Fon Mue, and Fon Dab. According to fieldwork among drummers in northern Thailand, the onomatopoeic terms for drum soundings include seventeen items: ga, pii, yoop, peng, pay, peung, teung, paeng, peeng, paueng, pa, toop, poop, teung, tuung, aung, and hong. When the drum ensemble accompanies Fon Nok (Bird Dance), the rhythmic pattern at the introduction is designed to be equal in parts, which can be identified as klong pi yoop or pay yoop. When the drum ensemble accompanies Fon To, it is found that each area has its own variation and version of drumming patterns. The toop item is used the dancer shakes his head and the peung item is used when the dancer rolls his body on the floor. The special technique for Klong Kon Yao is called look son when the drummer smashes on the drum head with the bottom side of his right palm. When the drum ensemble accompanies Fon Dab (Sword Dance) and Fon Meu (Hand Dance), the drummer sets up a rhythmic pattern. The look song is used as syncopation and it is sometimes used on downbeat. The other technique include yak na klong and dew dew techniques. When the drum ensemble accompanies the procession, the pattern is short and repetitive. The number of beats in each bar is equally distributed. Syncopation is found in the procession ensemble. The drum ensemble in Mae Hongson province is performed to accompany Fon Nok in slow tempo than the one accompanying Fon To. In contrary, the Tai people in Chiengmai usually perform in fast tempo for all dances. The continuity of klong kon yao ensembles remains to be fading due to the invasion of new technology which has great impact on the Tai’s way of life, although there is an attempt from education institution and government agents to help conserve the drum culture. The fieldwork reveals that the young generation is eager to participate in cultural activities to show off their talents in drumming, accompanying Fon Nok and Fon to, and securing their heritage.