Diet composition and food sources of the limpets Nacella deaurata and Nacella magellanica were studied in a subantarctic rocky-boulder intertidal system in the Magellan Strait, on the basis of gut contents and stable isotope analyses. Green microalgae (32.5 %), brown algae (22.2 %) and red algae (21.3 %) constituted the main food items in N. deaurata while green microalgae (28.3 %), micro-bivalves (27.4 %) and foraminiferans (20.9 %) were dominant food components in N. magellanica. Relative food items contribution indicated a generalist-type trophic strategy in both species, albeit N. deaurata exhibited a more pronounced herbivory. Stable isotope ratios confirmed this omnivorous / grazer lifestyle. Our results coincide with other studies that report green microalgae to be the major food item for other Nacella species but they also contradict the common view that these limpets are herbivorous animals.