Information on snake assemblages in Brazilian biomes has increased in the last decade. However, detailed studies on snake composition and natural history in urban fragments have never been conducted. The municipality of São Paulo has 150,900 ha and only 16% of forested areas, distributed in small and scattered fragments. Throughout 44 months of sampling, we registered in this municipality 38 snake species belonging to five families. Terrestrial frog-eater species were predominant. The number of recorded snakes was higher during the rainy season. Anual seasonality in captures might be related to prey availability and reproductive cycles. The most abundant species was Oxyrhopus guibei, with 24% of dominance, followed by Sibynomorphus mikanii (21%), and Bothrops jararaca (16%). Three species, Philodryas patagoniensis, Tomodon dorsatus, and Liotyphlops beui, were also common; six others were of intermediate abundance; and 23 were considered rare. Historically, the municipality of São Paulo showed a mosaic of different vegetational physiognomies. Nowadays, despite being fragmented due to the urban growth, these fragmented formations still enclose together a high richness of snake species.