The mite fauna of patches of High Arctic moss-grass tundra of Svalbard in Petuniabukta, Billefjord (moss, grasses, Salix polaris, bare soil), and adjacent to Vestpynten, Adventfjord (moss, moss mixed with grasses, Cassiope tetragona, S. polaris), were investigated. Our aim was to describe the mite fauna of this tundra with particular focus on the stage structure that is rarely investigated. We observed that the oribatid mites were distinctly more abundant and richer in species (22) than the gamasid mites (7) and their density and diversity varied between vegetation and location. Species diversity of Oribatida and Gamasida and the Shannon H′ index of mite communities were low, and Liochthonius sellnicki or Tectocepheus velatus dominated the Oribatida and Oppiella translamellata and Diapterobates notatus were relatively abundant, while the Gamasida were dominated by Arctoseius multidentatus, with Zercon forsslundi and Z. solenites relatively abundant. The juvenile densities of the Oribatida were usually greater than adults. Eniochthonius minutissimus and Metabelba sp. are new records for Svalbard.