The Chilean fog-free Pacific coastal desert, one of the driest desertic regions of the world, is undergoing rapid rates of desertification as a result of intensive agriculture, overgrazing and mining. There is an urgent need to document the mycorrhizal status of Chilean plants, and the role of the symbiosis in rehabilitation and preservation of species diversity. Here we present one of the first reports on the mycorrhizal status of annual and perennial herbs and shrubs from this region. Plants were collected during 1991 when rainfall was close to or above the annual average, providing the opportunity to asses several rare plant species. The plants examined included endemic species and endangered and rare geophytes. More than 90% of 38 species (19 families) were found to form exclusively arbuscular mycorrhizal fungi associations. Six species of mycorrhizal fungi were isolated from the root zones of plants sampled, four of which are undescribed.