The New Fire Ceremony is one of the few Aztec rituals documented in both the archaeological and historical records. The Spanish chroniclers described the New Fire Ceremony as an imperial celebration of the renewal of cosmic time that was observed on the local level by the renewal of household goods. George C. Vaillant first proposed the identification of artifact dumps at Aztec sites with descriptions of these local celebrations. We describe unpublished artifact dumps excavated by Vaillant at Chiconautla and Nonoalco in the Basin of Mexico and by Smith at Cuexcomate in Morelos and show that their context and content support Vaillant's hypothesis. Our data suggest that the New Fire Ceremony was an ancient and widespread ritual in Postclassic central Mexico that was appropriated by the Aztec empire as part of its program of ideological legitimization and control.