This paper presents the results of research on the dendroflora of the Natural Monument (NM) “Stari park” in Temerin, Serbia. The park’s natural values are intricately linked to the characteristics of its dendrofloristic elements, i.e. the large dimensions and age of its trees. To gain insight into changes in diversity, the flora recorded in 2004 and 2022 was compared. In 2022, a field study was conducted to provide a detailed dendroflora analysis, including taxonomic analysis, species origin analysis, assessment of the presence of autochthonous, allochthonous, and invasive species, as well as the biological spectrum. Although Celtis occidentalis L. remained the most represented species eighteen years later, its percentage decreased from 34% to 21%. This decline can be attributed to the emergence of new dominant species such as Fraxinus angustifolia Vahl. (15%), Ulmus effusa Willd. (13%), and Acer platanoides L. (9%). These four species now collectively constitute 58% of the trees in the park.