Abstract The Permian marine and continental sedimentary sequences in south central México and the biota contained in them are analyzed in this paper. The fossil flora and fauna are contained in Permian strata that correspond to the Guacamaya Formation in the states of Hidalgo and Veracruz; to the Patlanoaya, Los Hornos, Cuxtepeque, and Matzitzi Formations in the state of Puebla; to the Olinalá Formation in the state of Guerrero; to the Ihualtepec, Ixtaltepec, and Yododeñe Formations in the state of Oaxaca; and to the Paso Hondo Formation in the state of Chiapas. The microfaunistic association of Olinalá fusulinids can be correlated with the Guadalupe Mountains and the La Mar Formation of Texas in the U.S.A., and with the Difunta Formation of Coahuila and strata of the states of Sonora, Guerrero, and Oaxaca in Mexico. Fusulinids from the Olinalá, Ihualtepec, and Yododeñe Formations suggest that during the Late Permian (Wordian-Capitanian), these organisms were part of the same paleogeographic province that comprised Texas, Arizona, New Mexico, and California in the United States, and northern Sonora, Chihuahua, Coahuila, extending into central Mexico.