Apart from its aesthetic significance, urban greenery also plays a role in the social as well as ecological domain. The city of Zagreb may be proud of its numerous parks, tree alleys and ornamental gardens, making it easier to cope with the negative impacts of city life. Urban greenery systems often consist of sycamore trees, whose present-day appearance has been directly influenced over the years by various biotic and abiotic factors. One of the most important biotic factors, seriously undermining the vitality of the sycamore tree, is the harmful entomophauna. Sycamore lace bug (Corythuca ciliata Say) and the sycamore leafminer (Phyllonorycter platani Staudinger) are the most significant sycamore pests. In order to control them, it is important to monitor their population. The purpose of this research was to monitor the dynamics of occurrences of these two pests on three locations in Zagreb (Zrinjevac, Vukovarska street, Heinzelova street) in order to determine any changes compared to their position in 2016. The research was conducted by examining 20 leaves on 5 randomly selected trees, totaling at a number of 100 leaves altogether, every 7 to 10 days. The results differed depending on the location. According to data collected, the number of both pests was highest in Heinzelova street, and lowest in the park of Zrinjevac. Sycamore lace bug developed two generations on each location, but the rest two locations started developing mines of third generation. Our conclusion is that the dynamics and occurrences of the sycamore lace bug and the sycamore leafminer depend on the location, given that each location is under different influences. In order for the sycamore alleys to maintain their diverse role in the urban greenery system, more time should be devoted to developing a strategy of preserving the life cycle of these century old trees, since they are a proud tradition of the city of Zagreb. Combating pests and diseases of urban sycamore trees is often hard due to the proximity of people and animals, therefore attention should be focused on cheaper, effective and available methods, such as collecting and destroying fallen leaves, pruning and maintaining tree crowns and tree trunks. In case of chemical methods, special attention must be given to preserving biological diversity.