In general, faunal diversity increases with forest age; therefore, we predict that ant species richness in secondary forests will increase during succession and species composition will vary among different stages of succession. To test this hypothesis we describe the ant communities from five chronosequences comprised of forests that varied in the time lapsed since abandonment (i.e. 0-5 yr, 25-35 yr, and >60 yr). In each site, ants were sampled using baited traps, pitfall traps, and litter sampling. Ants were identified to species and species abundance per sample was recorded. A total of 21 ant species were collected. In all chronosequences, the 25-35 yr secondary forests had the highest ant richness. During this stage of succession, these forests have resources and microhabitats representative of both early successional forest (0-5 yr) and older successional forest (>60 yr). Thus, the ant species composition included both open-habitat and forest ant species. However, the overall composition of the 25-35 yr secondary forests displayed greater similarity to the composition of the >60 yr secondary forests. Similar results were obtained when we included two additional chronosequences and limited the analysis to litter ants. These results suggest that site age is a major force driving ant diversity and composition during plant secondary succession in Puerto Rico.College of Arts and Sciences University of Puerto Rico, Mayagüez