This document tries to describe in a provisional way the Ychsma cultural occupation of Armatambo archaeological site (south of Lima, Peru), during the Late Intermediate and Inca Periods. We start from our own investigations in the same site, that were carried out from 1998 until 2004. As a first step, we defined the necessity to separate the archeological discoveries with a local Ychsma character from the finds that express the Inca culture. This will permit us to start and build up a solid cultural secuence for Armatambo, in order to begin to understand the process of social structuring and Ychsma occupation in this part of Lima.