Abstract Many American cultivated species have been domesticated in the Neotropical Lowlands. While the southern limit of some cultivars (e.g. maize) is relatively well known for the Andean Region, the south-western limit of lowland horticulture has been poorly established in South America. Sixteenth-century European accounts mentioned the presence of cultivated plants in the Delta of the Paraná River, but until now this had not been confirmed by direct archaeobotanical data. This paper presents and discusses the results of starch grains analysis from six archaeological sites of the Paraná Delta (Argentina), ranging from 1302 to 1492 years cal. ad, which confirm the pre-Hispanic presence of cultivars in the area. Wild (algarrobo; South American mesquite) and domesticated (maize and beans) plant remains were found in ceramic containers and on grinding tools from those sites. Our research contributes new data on the late dispersion of cultivated species in the Paraná Delta, an area so far excluded from continental models for the dispersal of cultivars in the Americas.