This paper examines an obsidian cache offering excavated near the corner of a Postclassic Maya platform structure in Nojpeten, on the island of Flores, Guatemala. The cache consists of approximately 190 obsidian prismatic blade cores and core fragments, but the original number of cores placed in the cache likely fell between 173 and 182, with a best estimate of 177, 178, or 180. The cores were found about 20 cm southwest of the structure in a circular concentration measuring approximately 35 cm north-south by 30 cm east-west and 16 cm deep. The cache is analyzed through a lithic technology framework that focused on three phases: procurement, manufacture, and deposition. Data collection for the procurement phase consisted of sourcing the obsidian using a portable x-ray fluorescence spectrometer and obsidians from three sources in the Guatemalan highlands were found: Ixtepeque, San Martin Jilotepeque, and El Chayal. For the manufacture phase, data collection consisted of documenting core dimensions, degree and type of rejuvenation techniques, and the number and variability of platforms, blade terminations, and blade scars. This information was used to examine the prismatic blade-core technology responsible for creating this assemblage as well as to situate Nojpeten blade-core manufacturing within what is postulated for the greater Petén lakes region during the Postclassic period. To address the deposition phase, this paper examined the archaeological context of the cache by exploring the relationship the cores had with the adjacent structure, and the caching behaviors that resulted in this offering's deposition based on comparison with geographically, temporally, and compositionally similar caches. Analysis of this cache provides information on obsidian source utilization, exchange networks, prismatic blade core manufacturing practices, and caching behavior of the Itza Maya inhabitants of Nojpeten during the Postclassic.