Resumo. To investigate the ecological functions that squares play as urban green areas, this research was designed to inventory and characterize the vegetation used in the landscaping of the squares of Curitiba-PR state. All species occurring in 32 squares in the city were identified and quantified. Results show that 141 species were found, belonging to 58 families. Of this total, 60.3% of species are of arboreal life and 56.7% are of exotic origin. The species that appear in more places is Axonopus compressus (grama-são-carlos), present in 96.9% of cases. Between tree species, Ceiba speciosa (paineira) is the most frequent, appearing in 46.9% of the squares. Rhododendron simsii (azalea) had the highest number of individuals, with 438. It is important to consider the number of individuals, the diversity of species and their characteristics so that the ecological benefits provided by these squares can be guaranteed.