Mortuary practices of the Middle Preceramic period (ca. 8500-4000 B.P.) are discussed for the Nanchoc region of the upper Zaña Valley, northern Peru. Careful breaking, cutting, and placement of human bones from adult males during the Las Pircas Phase (8500-6000 B.P. ) gave way to more haphazard breakage and discard during the subsequent Tierra Blanca Phase (6000-5000 B.P.). The evidence of cannibalism is considered. Bone breakage, cutting, and possibly cannibalism is believed to have been part of a broader process of ritualization that mitigated the spiritual danger of the transition from hunting-gathering to horticulture