Soil chemical research has expanded and consolidated ideas regarding ancient Maya agriculture. Our team of soil scientists worked with archaeologists during 2005 to collect a variety of soil profile samples. We collected samples from seasonal wetlands in Tikal National Park, Guatemala. Profiles were analyzed at Brigham Young University for stable carbon isotope signatures in order to identify areas of maize cultivation. Crop residues from maize leave behind a distinct isotopic signature different from the normal or predominating rain forest vegetation in the area. We found evidence of maize cultivation in some locations in the wetland areas surrounding Tikal. However, this was not pervasive throughout every profile sampled. All of the wetland areas had variations in soil taxonomy and characteristics that may account for the different isotopic signatures. The results show cultivation was done and that further analysis of these wetlands can and should be done to improve our understanding of Maya agricultural practices.