This paper focuses on the study of mapudungun segmental phonology in general, and the phonetic- phonological status of the voiceless alveopalatal fricative phone [integral] in the chedungun spoken in the Alto Bio- Bio, in particular. Thus, in order to determine its occurrence and distribution, an adapted lexical list from Croese (1980) was applied to a total of 30 chedungun and Spanish bilingual adults collaborators belonging to 10 pehuenches villages of this commune (3 collaborators of each one). Through quantitative, spectrographic and distributional evidence, it is concluded that such phone occurs with a very low frequency, and in such cases it constitutes an allophonic variant of the voiceless alveopalatal affricate phoneme /(t integral) over cap/.