We conducted a floristic study and considered phytogeographical relations of the xeric scrubland in Tecozautla Valley, Hidalgo, Mexico. A total of 479 species of vascular plants, 298 genera, 80 families, and 51 infraspecific taxa were found. The most representative families are Asteraceae (62), Poaceae (46), and Fabaceae (33). Herbaceous plants are the dominant life form. Most of species are distributed in arid and semi-arid vegetation types. The 37.8% of the species were distributed in Mexico and 14.3% in the southern United States to Mexico. According to the similarity coefficient of Preston, 71% of the genera is shared with the Actopan Valley, 66% with El Olivo, Ixmiquilpan, both located in the Hidalgo state, 54% with the Sierra de Catorce, San Luis Potosi, and 50 % with Tehuacan-Cuicatlan Valley, Puebla and Oaxaca states. The higher affinity was found between the arid zone of Mezquital Valley and the southern portion of the Chihuahuan Desert in general. There are five associations of scrub vegetation: Fouqueria splendens-Agave striata, Mimosa-Myrtillocactus, Opuntia, Opuntia imbricata-Myrtillocactus, and Yucca. Due to lack of endemism, the floristic elements of the desert scrub of Tecozautla Valley, probably migrated to the area in recent times.