This study presents original data illustrating previously undescribed reduplicative patterns found in Tiriys, a Cariban language spoken in Northern Brazil; this is the first time that reduplication in a Cariban language is described in detail. One of the patterns is simpler, and its synchronic cases of variation suggest a certain path of historical evolution. For the other pattem, the complexity of the several subcases appear to indicate antiquity and make formal accounts significantly more difficult.