A study of the distribution and ecology of myxomycetes (plasmodial slime molds or myxogastrids) was carried out in the coastal and mountain forests of the geographically isolated island of Lubang in Occidental Mindoro of the Philippines. A total of 44 species were identified from moist chamber cultures. Arcyria cinerea , D. leucopodia , D. effusum , L. scintillans , and P. cinereum were the most abundant species recorded. Most species were commonly associated with only one of the substrates examined in two forest types. The highest level of productivity (myxomycetes recorded as either plasmodia or fruiting bodies) and the highest value for taxonomic diversity were observed for samples of ground litter collected from the mountain forests. However, the highest yield of fruiting bodies was noted for samples of the same substrate collected from the coastal forests. Assemblages of myxomycetes on Lubang Island were found to be similar within a particular area or forest type. This study is the first to compare the diversity and distribution of myxomycetes from two island forest types in the Philippines