Major social and economical changes occurred in human societies during the Iron Age of Southeastern Europe: increasing structuring of societies, intensifying production and metal technologies and the establishment of a market economy. However, the related plant economy of the region is still poorly studied and understood. The Iron Age `pit field sites' (groups of pits distributed over a certain area) in south-eastern Bulgaria were recently intensively excavated, and their study provides rich archaeobotanical assemblages, which are used for filling this gap in our knowledge. The current study presents the archaeobotanical information from 196 flotation samples from 50 Iron Age pits. The results show a wide range of annual crops, the most important of which seem to be hulled wheats (mainly einkorn), barley and also millet. A variety of pulses and fruits is retrieved, each in small quantities. Some species like Olea europaea and Cucumis melo are an indication for contacts with adjacent regions (especially the Mediterranean area). The archaeobotanical assemblages also documented the environment and land use, revealing the exploitation of a variety of habitats like cropland, open grassland, shrub land and wetland. The archaeobotanical analyses of the Iron Age pit fields show that this type of structures can be an important source of information on the Iron Age plant economy in the region.