Tropical pasture legumes of the genus Centrosema and Stylosanthes have been evaluated in past years in contrasting regions of Costa Rica. More recently, a large number of accessions terminated a 2-year cutting period in humid, subhumid and seasonal tropical forest sites. The latter is characterized by acid soils (pH 4.6) and high Al concentration, while acidity is moderately in the others (pH 5.5 to 5.9). Site x species interaction was significant (P < 0.05) in terms of monthly dry matter yields (MDM), and with the exceptions of £. pubescens• site x accession interaction was also significant for all other species. Adaptation, measured as total MDM, was significantly high (P < 0.05) in humid tropics for all species. The accessions CIAT 5189, 5172, 438 and 442 of £. pubescens adapted similarly in both subhumid and seasonal forest; the same occurred for the accessions CIAT 184, 21 and 136 of cruianensis. this species showed the widest range of adaptation. £. acutifolium CIAT 5568 outyield CIAT 5277 (393 and 167 kg MDM respectively), while accessions CIAT 5735, 5674, 5065, 5452 And 5733 of Q. macrocaroum produced higher yields in conditions of subhumid tropics as compared to seasonal forest, due mainly to high incidence of foliar diseases (Cercospora. Cylindrocladium and bacteriosis) in the latter site.