Protected areas are one of the main strategies of biodiversity conservation. However, if these areas do not coincide spatially with priority areas for conservation, they may not fully achieve their objective. Cactaceae is one of the most frequent plant families in the drylands of the neotropical region, but also one of the most threatened. Our objective was to understand whether the protected areas in the Brazilian semiarid region (Caatinga) include hotspots of the Cactaceae family. For this, we used distribution models of 81 species to calculate the corrected weighted endemism index (CWEI) and compared it with the size and location of 160 protected areas that currently exist in the region. Our results show that 4.7% of the area with the highest CWEI occur within protected areas, especially in those with fully protected status (the highest protection level according to Brazilian legislation, which is equivalent to IUCN categories I to III). However, 99.3% (75,758 km(2)) of the summed protected areas have a low or very low CWEI, and only 0.7% (532 km(2)) have a high or very high CWEI. These results suggest the importance of reassessing priority areas for in situ conservation of Cactaceae in the Caatinga region.