Parque Estadual do Juquery is the largest protected remnant of savanna grassland in the metropolitan region of Sao Paulo (MRSP). We conducted a floristic inventory and created a photographic record of the angiosperm flora of the savanna formations in this area and compared it with those of other Cerrado sites using Jaccard's similarity index. We present a list with 366 species, distributed in 58 botanical families. Asteraceae and Poaceae were the families with the highest species richness. Eighty-six new occurrences were recorded in the park. According to the Sao Paulo state Red List, 14 species are threatened by extinction, of which four are presumably extinct. Most species are herbaceous (36.0%) and sub-shrub plants (26.5%). No floristic similarity was observed with other savanna formations in the countryside of the state of Sao Paulo. Our results emphasize the importance of the Parque Estadual do Juquery for the conservation of savanna grassland formations in the MRSP and the protection of locally endangered species. Keywords Brazilian savanna, floristic inventory, old-growth grassland, Poaceae, Asteraceae, tropical grassland