Resumo. Semideciduous forests occur in a few places in the Cerrado biome, but are being suppressed through by agriculture and livestock in central Brazil. The objective of this study was characterize the horizontal and vertical structures, the dispersal syndromes, successional groups and floristic similarity of the tree layer and regeneration in a semideciduous forest fragment in Itumbiara, Goiás state. All trees alive with circumference at breast height (CAP) ≥ 15 were identified and measured for height and diameter in 25 plots of 20 x 20 m. To the regenerative stratum the criteria was the inclusion of individuals with height ≥ 1m until CAP = 14.9 cm in 25 plots of 10 × 10 m. In both layers were sampled 100 species. The species with the highest importance in the tree layer were Nectandra megapotamica (Spreng.) Mez, and in the regenerative stratum, Siparuna guianensis Aubl. Both layers had a higher proportion of early secondary species and the zoochory dispersion syndrome was more frequent. Several important species are not represented in other semideciduous forests, and then this forest is an important permanent conservation area.