It is currently estimated that the globe is home to more than 1.5 million species of fungi, of which approximately 70,000-150,000 are found in Thailand. However, compared with other major groups (e.g. higher plants and animals) fungi are poorly researched, and to date only 80,000 species have been documented worldwide. Although Thailand has a long tradition of studying the fungal pathogens of economically important plants, it is only in the last ten years that significant efforts have been made to survey the vast biodiversity of fungi in Thailand’s natural ecosystems. In 1993, BIOTEC established the Mycology Research Program to study the biodiversity of invertebrate pathogenic fungi in the Kingdom, and over the past ten years the activities of the program have broadened to include other groups of fungi such as alkaline tolerant fungi, dung fungi, freshwater fungi, lichen fungi, litter Basidiomycetes, marine fungi, palm fungi and seed fungi. More recently, numerous different taxonomic and ecological groups of fungi have been added to the research activities of the program, the overall aims of which are provided data on the biodiversity of fungi in Thailand, isolate fungi for the BIOTEC Culture Collection and screening programs, and develop an information resource on fungi which can be made widely available.