The Philippines has a poorly documented microbial flora and this is particularly true for myxomycetes. Thus, the research project described herein was carried out to assess the occurrence, distribution and diversity of the communities of myxomycetes in Mt. Arayat National Park. A total of 21 species representing 11 genera were recorded from substrates collected along two transects (Baño and Magalang) located in Mt. Arayat during the wet and dry season. Samples collected during the dry season, along the Magalang Trail, and aerial litter were the most taxonomically diverse, whereas the highest values for species diversity were observed for the Baño Trail, ground leaf litter and the dry season. Comparisons of the myxomycete communities yielded relatively high coefficient of community (CC) and percentage similarity (PS) values for the dry and wet seasons. This is the first study for the Philippines that has attempted to document the species composition of myxomycetes and their abundance in relation to the time of year they were collected, differences that exist between sites and substrates upon which these organisms occur.