This thesis is the isotopic dietary study of two Postclassic Maya archaeological sites of El Rey and San Miguelito on the Island of Cancun in the Yucatan Peninsula. A bone and tooth sample were used from the individuals in the selected study populations and processed to extract carbonate and collagen to be analyzed for carbon and nitrogen isotopes to determine the dietary utilization of maize and marine protein of these two populations. At this point, the collagen results have not been received from the laboratory and are not part of the conclusions. The carbonate results indicated that the populations were utilizing marine resources available to them. Previous research, based on Sr isotopic data, indicated that four of the individuals at El Rey were not from the island originally and the isotopic evidence indicates that these individuals adopted the eating practices of the local populace of the Island of Cancun. The results indicate no stark differences in the diet, which indicates that the communities on the island were more egalitarian, or, at least, that status was not tied to food consumption.