Increased temperatures are altering biogeochemical processes in wetland ecosystems. In the SPRUCE experiment, a whole-ecosystem warming and elevated atmospheric CO2 manipulation in an ombrotrophic peatland in northern Minnesota, USA, we are examining how warming affects solute concentrations and fluxes from peatland streams. After 10 years, total organic carbon concentrations almost doubled with warming (up to +9°C). In contrast, there was a muted increase in nitrogen and phosphorus concentrations, likely due to biological uptake in this nutrient-limited ecosystem. While solute concentrations generally increased with warming, stream flow decreased, likely due to increased evapotranspiration, resulting in an overall decrease in total organic carbon and nutrient efflux (in the early years) or no change (in the later years) with warming. These results will be put into context of the peatland carbon budget to evaluate the extent to which warming influences the carbon balance of these vulnerable ecosystems.