Although bees have been demonstrated to be abundant and species-rich in cities, several studies pointed out that oligolectic species are scarce in those urban landscapes. Oligolectic species are those whose females collect pollen from a few closely related plant species or from some species belonging to the same or related plant families. We studied three nest aggregations of the oligolectic bee Centris collaris (Apidae) in an urban area. Nest aggregations were found underneath building ramps at a university campus within the city of Uberlândia, southeastern Brazil. Females were observed in nesting activity from April to May 2016. The analysis of satellite images of a 2.57-km² area revealed that only 0.15% was suitable for nesting sites, i.e. areas of exposed soils. Seventeen plant species were identified as floral sources of C. collaris through the pollen analysis of 43 females' scopae. The interaction analysis produced a highly specialized network (C = 0.314, H₂′ = 0.744). The numbers of interactions of the plant species Senna pendula (Fabaceae), Malpighia emarginata (Malpighiaceae) and Dioclea violacea (Fabaceae) with C. collaris females were the highest, and those plants were classified as the main sources of pollen, oil, and nectar, respectively. Our results showed that in spite of the negative effects of urbanization, a small population of the oligolectic C. collaris could find places that met its biological requirements (floral resources, nesting sites) allowing for a long-term establishment in an urban area. Preservation of exposed soil areas as well as the use of native plants in urban forestry and gardening, especially those species visited by oligolectic bees, would be important measures to be adopted for bee conservation in cities.