Plant macrofossils from the underwater archaeological site of the ancient port in Zaton near Nin were analyzed by applying archaeobotanical methods. The samples were collected in 2011 and 2012 in collaboration with the hydro-archaeologists from Department of submarine archeology of the Archaeological Museum in Zadar. There were 39 samples analyzed from the year of 2011., and 23 samples from the year of 2012. dating back to first to mid-fourth century. In both years there were 4320 plant residues extracted from all samples, most of which were determined to species level. Fragments or whole remains of seeds, fruits, twigs, leaves, and thorns were found. Results of the analysis confirmed that three most important agricultural products were: grapevine (Vitis vinifera L.), olive (Olea europaea L.) and fig (Ficus carica L.). Cherry (Prunus avium/cerasus L), peach (Prunus persica (L.) Batsch), stonepine (Pinus pinea L.), almond (Prunus dulcis (Mill.) D.A. Webb), walnut (Juglans regia L.), chestnut (Castanea sativa Miller), herbs and vegetables were also grown. On this site there was an important finding of radish seeds (Raphanus sativus L.) which is the oldest finding of radish in Europe, and sebesten fruits (Cordia myxa L.) which is very rare found on archaeological sites in Europe. Another interesting find is Glaucium corniculatum (L.) Rudolph which is not autochthonous in Croatia.