Infrared absorption spectroscopic identifications of various cellulosic, polyester and T/C blended fibers were discussed in this paper. For this method the necessary amount of samples are very small, and identification of textile fibers is generally simple. Detection of functional groups in blended fibers is easily performed by the use of characteristic absorption band. The potassium bromide pressed disc technique was used to study the behavior of the T/C blended fibers in the infrared region. These spectra can be used to measure the content of blended fibers from the ratio of CH stretching band (2900cm-1) of cellulose to C=O stretching band (1720cm-1) of polyester fibers. Absorbance by chemical structures in fiber is function of the transparency of the potassium bromide disc. (Received March 10, 1971)