Karst forest represents a distinct landscape with highly alkaline soil and limestone rocks. This specialized topography supports many unique species of plants and animals. Thus, documenting species in this area is important for any biodiversity research. In this study, a field survey was conducted to assess abundance, diversity, and distribution of myxomycetes in a karst forest within Quezon National Park, Philippines. Fruiting bodies were collected in addition to decaying substrates (e.g., aerial leaves and ground leaf litter) and twigs for culture in moist chambers. A total of 35 species from 16 genera was identified. The majority of these species occurred only rarely. Myxomycete communities between aerial and ground litter had the highest level of similarity based on their species composition and corresponding relative abundance. This study documented diversity of myxomycetes from the lowland karst landscape in the Philippines and now serves as baseline information for investigating plasmodial slime molds in Quezon National Park.