Headdresses have been considered key artifacts for the study of the Andean costume, due to their symbolic and technological characteristics that allow addressing aspects like individual identity, social status and cultural interactions. The Instituto de lnvestigaci6n Arqueol6gica R.P. Gustavo le Paige, located in the Antofagasta Region, north of Chile, houses a valuable collection of pre-Hispanic headdresses, which are associated with funerary contexts in the Atacamenian culture. The most representative type of hat consists of two independent structures: cap and hatband. This type of hat has been recorded from the period of Tiwanaku State influx in San Pedro de Atacama area. This article presents the documentation, diagnosis and treatment of an Atacamenian headdress with no contextual information. The research was mainly focused on the identification of its technological characteristics, and on determining symptoms of alteration and deterioration of the object at a superficial and a structural level. The main goal of the procedures applied was to recover the semispherical shape of the cap and to remove elements and residue adhered to it surface.