An isotopic reconstruction of human dietary patterns and livestock management practices (herding, grazing, foddering, etc.) is presented here from the sites of Düzen Tepe and Sagalassos in southwestern Turkey. Carbon and nitrogen stable isotope ratios were determined from bone collagen extracted from humans (n = 49) and animals (n = 454) from five distinct time periods: Classical-Hellenistic (400–200 BC), Early to Middle Imperial (25 BC–300 AD), Late Imperial (300–450 AD), Early Byzantine (450–600 AD), and Middle Byzantine (800–1200 AD). The humans had protein sources that were based on C3 plants and terrestrial animals. During the Classical-Hellenistic period, all of the domestic animals had δ13C and δ15N signatures that clustered together; evidence that the animals were herded in the same area or kept in enclosures and fed on similar foods. The diachronic analysis of the isotopic trends in the dogs, cattle, pigs, sheep, and goats highlighted subtle but distinct variations in these animals. The δ13C values of the dogs and cattle increased (reflecting C4 plant consumption) during the Imperial and Byzantine periods, but the pigs and the goats displayed little change and a constant C3 plant-based diet. The sheep had a variable δ13C pattern reflecting periods of greater and lesser consumption of C4 plants in the diet. In addition, the δ15N values of the dogs, pigs, cattle, and sheep increase substantially from the Classical-Hellenistic to the Imperial periods reflecting a possible increase in protein consumption, but the goats showed a decrease. Finally, these isotopic results are discussed in the context of zooarcheological, archeobotanical, and trace element evidence. Am J Phys Anthropol 149:157–171, 2012. © Wiley Periodicals, Inc.