Situated near the current Denizli, the city of Hierapolis was established in the IIIrd century BC, then was particularly developed during roman and byzantine periods. Since the first campaign of excavation in 1957, the importance of the antique necropolis in the North of the city has been recognized, this has led to develop certain number of studies relative to the architecture of graves and to the epigraphy. Nevertheless, few things are really known on the functioning of sepultures and several questions concerning the funeral gestures and practices remain unanswered: what modes of inhumation were privileged? Were there post-mortem re-interventions? What can we say about the biological identity of the buried individus? To answer these problematics, an archeo-anthropological investigation is currently in progress in the subterranean chamber of a collective tomb from imperial time. This chamber, interpreted as a familial sepulture, was found intact, and will allow to increase our knowledge on the funeral antique practices. In parallel, a second grave also dated from imperial period is studying; situated in the East necropolis, its nearness with the place where Saint Philippe has been tortured, entailed its reopening and the deposit of pilgrims' body during byzantine time. Its complex functioning allows to understand the evolution of this major sector in the history of Hierapolis.