The Arctic plays a key role in the Earths climate system, because global warming is predicted to be most pronounced at high latitudes, and one third of the global carbon pool is stored in ecosystems of the northern latitudes. The degradation of permafrost and the associated intensified release of methane, a climate-relevant trace gas, represent potential environmental hazards. The microorganisms driving methane production and oxidation in Arctic permafrost soils have remained poorly investigated. Their population structure and reaction to environmental change is largely unknown, which means that also an important part of the process knowledge on methane fluxes in permafrost ecosystems is far from completely understood. This hampers prediction of the effects of climate warming on arctic methane fluxes. Further research on the stability of the methane cycling communities is therefore highly important for understanding the effects of a warming Arctic on the global climate. This review first examines the methane cycle in permafrost soils and the involved microorganisms. It then describes some aspects of the potential impact of global warming on the methanogenic and methanotrophic communities.