Cold biomes significantly contribute to the global carbon cycle, and decomposition in these ecosystems is expected to be affected by climatic change. Modifications of snow cover patterns are expected to affect litter decomposition, but the underlying mechanisms remain unclear. In this study, we investigated whether soil meso- and microfauna significantly contribute to wintertime decomposition. Using litterbags with two mesh sizes (68 µm and 1500 µm), we found that small mesh litterbags reduced winter decomposition in the field by 3.4 % for Patzkea paniculata litter and by 18.9 % for Dactylis glomerata litter, indicating a significant contribution of soil meso- and microfauna to litter decomposition under the snowpack. Whereas previous studies showed that winter decomposition was not related to the soil fauna community, our results suggest that this community, and its possible alteration by climate change, may impact litter decomposition and carbon dynamics in cold biomes.