The aim of phytogeographical analysis was to determine the plant species origin, genesis and migrations. The study results contribute to the knowledge of phytogeographical classification of the particular regions. The flora structure and composition was determined based on the effects of different chorions. The aim of the floristic research of flood forests of Ravni Srem was to identify the diversity of flora in the region, i.e., in a wider sense, the diversity of flora in Serbia. The phytogeographical analysis was based on floristic research. The identified plant species were classified into the corresponding floral elements, area groups, and area types. The data on their diversity and the degree of representation in the flora of Ravni Srem flood forests were obtained based on the percentage of each area type. It was concluded that the character of the flora of Ravni Srem flood forests was transitional, mostly Eurasian-Central European.