Eight burials were found when the Archaic phase at the ancient site of Gabii was excavated between 2008 and 2010. Stable isotope analysis was conducted using the ribs from seven adult individuals and one pelvic bone from an infant in order to reconstruct their dietary patterns and learn more about this relatively unexplored time period. The 15N (9.3 to 11.5) and 3Cco (-20.5 to -18.9) from bone collagen, and the 13Cap (-13.2 to -9.5) from the apatite, demonstrate that Archaic Gabines' diet consisted mainly of terrestrial protein in conjunction with C3 plants. When comparing their 15N and 13C ratios to Imperial period samples, there is shift towards positive values, suggesting that Imperial Gabines were eating more marine resources and more C4 plants than were Archaic Gabines. Nonetheless, when combining Gabii's isotopic data with another suburban Roman site, Castellaccio Europarco, Gabines were eating fewer C4 plants, but more marine foods than the people from Castellaccio Europarco. Overall, there seems to have been a shift over time that might coincide with the growth of the Republic and subsequent Empire. The results of this study demonstrate the usefulness of stable isotope analysis on bioarchaeological samples to reconstruct past diet and overall health.