Since the first investigations, the Paracas and Nasca have been considered as two of the most representative social formations of the Peruvian south coast. Elements indicating interaction with the highlands were identified only for the latest phases of the stylistic sequence of Nasca pottery, especially those related to the characteristic ceramic style of the Wari state that emerged near the modern city of Ayacucho, during the Middle Horizon. However, in the last years, fieldwork carried out in the Palpa valleys and its tributaries resulted in increasing evidence of Paracas and Nasca sites in the highlands. This new evidence forces us to reconsider our traditional concepts of Paracas and Nasca settlement patterns and socioeconomic structures, including the transitional epoch between them. Since 2006, members of the Palpa-Lucanas Archaeological Project conducted intensive fieldwork in the catchment area of the northern tributaries of the Nasca drainage, especially in the highest sections of the Palpa and Viscas valleys. The surveys reached up to the highest points of the western slope of the Andes, at an altitude of 4300 m above sea level. Thus, the inventory of the archaeological sites on the west side of the Andes, including coastal, yunga, and highlanders, now comprises about 1500 sites belonging almost to all time periods. In this paper we present the results of our studies in the highlands, emphasizing those related to the Paracas and Nasca, and especially to the transition between them, which shows strong relationships with the Topara tradition. Excavations on Cutamalla and Huayuncalla sites provide relevant stratigraphic data to the theme presented here. [ABSTRACT FROM AUTHOR]