Haloaleurodiscus gen. nov. (Homobasidiomycetes) is described from Japanese mangrove forests with one species H. mangrovei sp. nov. The genus is morphologically characterized by having resupinate basidioma, nodose-septate hyphae, sulphoaldehyde-positive gloeocystidia, dendrohyphidia and amyloid basidiospores with minute warts. These morphological features are similar to those of Aleurodiscus s. lat., but H. mangrovei differs from the Aleurodiscus primarily in occurring in white pocket-rot and is not closely related based on ribosomal DNA sequence analyses. Molecular data suggest that this species is phylogenetically placed in the root of the 'Peniophorales' clade. In addition, ecological and physiological features of the species are provided.