The flora and vegetation studies that have been carried out in the El Retiro Natural Reserve have been limited to some of its sectors, so there is still no information regarding the structure of it's plant formations and the relationship between them. Therefore, the objective of this investigation was characterize the vegetation of this protected area. The following aspects were analyzed: dominant species, stratification and distribution in all types of vegetation. It obtained a map with a greater level of detail of the distribution of the plant formation in the area. Seven types of vegetation were identified, of which the secondary scrub in semideciduous microphyll forest ecotopes and the secondary scrub in coastal and precoastal scrub ecotopes resulted in new vegetation records for the reserve. The coastal and precoastal scrub and the semideciduous microphyll forest were the richest plant formations in number of species and endemic. In the biological similarity analysis, these turned out to be the ones with the highest affinity.