The aim of this study was to evaluate the effect of island area and isolation on species richness and abundance, and vegetation structure of Isla Palma by comparing these parameters with those of the continental location, Playa Chucheros. By sampling vegetation at each locality using Gentry transects (10 50x2 m) we found 204 species of plants at Playa Chucheros, and 103 on Isla Palma. Species richness and abundance of woody plants was higher for Playa Chucheros (472 individuals) compared to Isla Palma (349 individuals). Richness estimators indicate that the plant species richness of Playa Chucheros is almost twice as high as that of Isla Palma. Rarefaction curves suggest that Playa Chucheros had a significantly greater richness than Isla Palma. Furthermore, physiognomic parameters were higher for Playa Chucheros than those observed for Isla Palma, showing that the former supports tree vegetation with higher DBH and greater height. These results indicate that the size and isolation of the island is reflected in a diminished richness and vegetation structure, which can be of significant assistance in the development of better conservation strategies for plants and other groups of organisms on islands.