During the years 2000 and 2001, a project was carried out to determine the paleoclimate in the Valley of Guatemala. There were two main objectives: (1) to compare and contrast the Highland data with that already obtained from the Maya Lowlands and the Caribbean region; and (2) to understand the relationship between climate and the disappearance of lakes and irrigated agriculture at the archaeological site of Kaminaljuyu in the Valley of Guatemala. Sediment cores have been recovered from Lake Amatitlan and the extinct Lake Miraflores associated with Kaminaljuyu. The samples have been transported to the United States for radiocarbon dating and for analysis of microfossils and pollen content. The paper summarizes the work and the results of the analysis obtained to the present.