The alien tree species Spathodea campanulata forms monodominant stands in abandoned agricultural lands in Puerto Rico. In July 2005, we excavated three replicate randomly located soil pits (25 by 25 by 30 cm) in each of six stands of Spathodea. Three of the stands were located in the moist alluvial geoclimatic zone and three were in the moist karst geoclimatic zone, all in the north coast of Puerto Rico. We examined all the soil by hand, sampled, and counted all the earthworms, determined their fresh weight, and identified them to species. Earthworms were absent from all nine pits in the karst forest. Earthworm density in the alluvial forest averaged 84/m2 or 279/m3,representing an earthworm fresh weight of 47 g/m2 or 157 g/m3. Four species of earthworms were present in our sampling: Onychochaeta borincana, Pontoscolex spiralis,P. cynthiae, and P. corethrurus. Of these, P. corethrurus is an alien, and the other three are native species. Pontoscolex spiralis usually lives in wet conditions, while O. borincana and P. corethrurus are indicators of disturbed conditions. The density and biomass of earthworms in the alluvial forest are comparable to density and biomass in other Puerto Rican forests. The absence of earthworms in the same kinds of stands in karst forests may imply either a clumped distribution of earthworms in those forests or else the animals were located deeper in the soil profile.College of Arts and Sciences University of Puerto Rico, Mayagüez