The object of this thesis is the ritual-musical system called A Dança dos Aruanãs amongst the Javaé, immemorial habitants of Rio Araguaia, in special of the region of Ilha do Bananal (TO) and surroundings (at east), known as a sub-group of Karajá in general (Karajá, Xambóia and Javaé), pertaining to Macro-Jê linguistic stock. The purpose of the present study was to describe the contemporary constitution of this ritual based in ethnological, historical and musicological data. It is intended to comprehend how a ritual-musical is constituted, taking the structure of myth-music-dance as central focus, structure which the music operates as central axle in the mythcosmology connection with body arts (dance, featherwork and ornamentation). The ethnography aims a density description as from the ceremonial life, centered in three aspects: musicality, corporality and ritual performance. The plays of Aruanãs are rituals of one or two annual cycles, having as sociological armour, the kinship matrimonial service.