At the end of the 19th century the continually progressive changes in the traditional principles related to techniques, expressions, structure, style, essence, and content directed the composers to explore a new musical language. Composers began to utilize novel musical elements such as unusual accentuations and rhythms in their compositions, as opposed to concentrating on conventional melodic and harmonic means employed up until that time. Instrumental colors, a vast range of dynamics, accents, pulse and texture became the most significant elements in music. In the 20th century, along with the use of conventional performance techniques, increasing the spectrum of instrumental colors and expanding the timbrel features of instruments, thereby exploring all new sound possibilities, supported the emergence of "extended techniques" in flute. With the enhanced timbrel varieties achieved through these extended techniques along with its standard performance techniques, the flute became one of the most preferred instruments by 20th century composers. In this study, with the gleams of timbrel richness resulting from these extended techniques in flute such as flutter-tonguing, microtones, glissando, multiphonics, key clicks, and sing-and-play, selected examples will be given from pioneer composers E. Varese, A. Jolivet, L. Berio, R. Aitken, R. Dick who employed these extended techniques in their compositions respectively entitled "Density 21.5", "Cinq Incantation", "Sequenza I", "Icicle" and "Lookout". Keywords: Flute, Extended Techniques, Multiphonic, Microtone, , Density 21.5, Cinq Incantation, Sequenza I, Icicle, Lookout