The study was aimed at determining the species composition of aphid fauna related to the dendroflora of Kórnik Arboretum as well as determining the infestation level of trees and shrubs. The infestation level was measured on a five-level scale. The material was collected on two sites: in a park and forest. 236 botanic taxa (species and cultivars) were confirmed to be infested by aphids in Kórnik Arboretum; the taxa belonged to 22 families and 46 genera of Angiospermae and 2 families and 6 genera of Gymnospermae. The collected aphid fauna included 96 species of Aphidoidea and Phylloxeroidea superfamilies. The botanic taxa most threatened with damage resulting from the insects feeding, and consequently a loss of decorative value, were defined.