The thesis titled “LAKORN CHATREE VOCAL STYLE OF KRU MANTANA YUYANGYUEN” is aimed at examining the background and unique melodies of Chatree dramatic singing styles by Fine Arts Department and the vocal techniques of Master Mantana Yuyangyuen in the Chatree drama Rodasen from 10 songs. The research bindings show that Chatree drama is a very old dance drama with a legend related to folk literature. When the Chatree drama was revived by the Fine Arts Department, the department invited the Chatree drama troupe of Mr. Poon Rueangnon to interpret it. Mr. Thongbai Rueangnon, who was his son, being the interpreter, and Master Montree Tramote modified the melodies. As for the musical instruments and instrumentation, formerly there were Javanese clarinet, tone, Chatree drum, double gong, small cup-shaped cymbals and wooden rhythm clappers. The development by the Fine Arts Department is the inclusion of the gamelan with padded hammers in the ensemble. The Fine Arts Department excluded the Chatree prelude melody leaving only the drum roll part, and due to the fact that the performers who are the dancers are just dancers who have the singers doing the singing for them. The Chatree plays of the Fine Arts Department are unique for both the songs and the singing. The song that has always been sung from the past is a song derived from the Chatree drama troupe of Mr. Poon Rueangnon. “Rai Chatree” This song is entitled and the song found in the collection of songs in twelve languages. Master Montree Tramote put this song in the Chatree play Rodasen is “Chatree Talung”. As for the songs newly composed by Master Montree Tramote, there are “Linglode Chatree”, “Chatree Krub”, “Rai Chatree 3”, “Rai Chatree 2”, “Chatree Baang Chaang”, “Lam Chatree” and “Tayoi Dong”. The singing parts with a main theme are found in 2 songs, namely, “Chatree Talung” and “Chatree Baang Chaang”. The other 8 songs only have melodies for singing, namely, “Linglode Chatree”, “Chatree Krub”, “Rai Chatree 3”, “Chatree 2”, “Rai Chatree”, “Lam Chatree”, “Tayoi Dong” and “O Baang Chaang”. For most of the melodies, the Piang O Laang range was used for the principal part. Almost all of the closing melodies end with the first tone of the Piang O Laang range. Most of the determined ending pitches (looktok) are the sol tone. Regarding the style of melodies, from all the songs, melodic repetition is found less than the use of non-repeated melody and there is variation of melodies. It is found that the singing techniques of Master Mantana Yuyangyuen in the Chatree dramas are used according to the patterns of the Fine Arts Department modified by Master Montree Tramote. The vocalization is done according to the manner of singing led by the main theme. As for the lyrics, Master Mantana added the lyrics in the style of general Thai songs with melodies in the Na Tub Prob Kai rhythm in the 2nd tempo level. Regarding the use of the beginning tone, it is found that the melodies in the Piang O Laang range begin with the first, second, third and sixth tone of the range. Melodies guided by the middle range begin with the sixth tone of the main line and the songs guided by the Piang O Bon line begin with the second and sixth sound. Moreover, Master Mantana employed 6 singing techniques in all, namely, word-shaping, ringing, gliding upward, reversing, pressing the voice low and variation of ending. The technique that is found to be most used is word-shaping.