Urban flora has an important impact on public health, and this aerobiological research proposes for the first time in Croatia a new and original way of estimating the allergenic index of flora, on the city of Zadar case study, for the period 2007-2015. All obtained values of allergenic index are <0.5 and the hypothesis that the allergenic potential of the urban flora of Zadar does not pose a high health risk was confirmed. Standard aerobiological analyzes show the dominance of pollen of tree taxa (72.7 %) during the winter-spring months and weeds (24.4 %) and grasses (3.0 %) during the summer-autumn months, and the main pollen types are Cupressaceae, Olea spp. and Urticaceae. Correlations between numerous meteorological parameters and concentrations of the most common pollen allergens were established (eg temperature in many taxa has a positive and precipitation a negative correlation) and a pollen calendar for the city of Zadar was developed. The conducted research shows that the area of the city of Zadar can be considered as an area of low allergenic potential and that the proposed allergen index can be used as a tool for selecting the most suitable plants for urban planning of green areas.