The collapse of the Tiwanaku state around AD 1000 resulted in dramatic changes in the areas of its former colonies such as the Moquegua Valley, which featured the largest Tiwanaku communities outside the Altiplano. The inhabitants of these former colonies were forced to relocate to the areas north of Moquegua, including the Tambo River estuary (Arequipa Department, Province of Islay). This relocation has been confirmed at La Pampilla 1, where a large graveyard featuring funerary contexts of the postcollapse communities of Tiwanaku-Timulaca was found, with a calibrated 14C date between the eleventh and thirteenth centuries AD. In this article we discuss the results of excavations and analyses conducted at the La Pampilla 1 graveyard, the first systematically researched Tiwanaku site in the Tambo Valley: these findings confirm the existence of a relatively large, terminal-phase Tiwanaku population, represented by Tumilaca funerary contexts.