This paper presents the results of an investigation conducted on the rock art of the Los Fierros archaeological site. The site is situated at the summit of Cerro Los Fierros, at 1200 masl, near the town of Las Carditas, about 7 km from the urban center of Andacollo (Coquimbo region, Chile). Through the formal analysis of intrinsic attributes of the existing rock art, the authors were able to identify the chronologicalcultural periods during which these expressions were produced, and which human groups created them. The analysis yielded a substantial quantity of designs produced in historical times, which until now had not been documented nor recognised, and which correspond mainly to motifs known as cattle brands.