This study makes a characterization of arboreal vegetation in two ravines in Tlatlaya region, Mexico State, located in Rio Balsas basin, it remarks the presence of Subdeciduous Tropical Forest in the State and presents a 251 species list of vascular plants, included in 83 families and 182 genera. In the zone, it were found 42 tree species with higher importance values belonging to Guarea glabra (64.98 and 96.95) and Eugenia acapulcensis (28.30 and 84.51). The paper shows individual density values, diversity, dominance, importance values and evenness index for arboreal contingent in such ravines.
