Leaf-litter decomposition plays an essential role in the functioning of stream ecosystems. This process, driven by microbial and invertebrate communities, is likely to be severely affected in a context of climate change and increased water abstractions. The occurrence, frequency and severity of drying events are increasing in rivers worldwide, and represent a major threat to aquatic communities and their contribution to riverine biogeochemical processes. While a growing body of evidence suggests a dramatic reduction in litter processing rates during emersion phases, the effects of emersion frequency have been in contrast overlooked. We hypothesized that, in response to repeated cycles of emersion and immersion, a change in the structure of decomposer communities would translate into a modification in litter processing rates. We exposed Alnus glutinosa L. litter-bags to 5 different treatments consisting in repeated cycles of emersion and immersion in the Albarine river (Eastern France). We used litter bags with two mesh sizes to determine the relative contribution of microbial and invertebrate communities to leaf-litter processing. After 30 days of incubation, leaf mass loss and invertebrate abundances and biomass were determined. We also determined the biomass and structure (molecular fingerprint) of fungal and bacterial communities developed on leaves. Our results indicated a negative influence of emersion duration on leaf-litter processing. However, no significant influence of emersion frequency could be detected in the present study. Fungal and bacterial biomasses were positively correlated with immersion duration and microbial biomass was dominated by fungi at the end of the incubation period. Fungal and bacterial community structures were relatively insensitive to the frequency of emersion. Invertebrate communities had no influence on leaf litter processing and leaf-mass loss was mainly driven by aquatic fungi. Our findings suggest that the observed modifications in the structure of decomposer communities were only partly reflected by a change in leaf-litter processing rates.