Riparian zones are important transition zones where nutrients can be removed by plants or transformed by microbes.  Invasive earthworms can affect nutrient cycling in soils and can reach high densities in riparian zones.  Our objective was to examine how invasive earthworms affect nutrient flux from riparian zones to nearby streams and how this flux affects periphyton growth.  Each of 16 artificial streams was paired with a riparian soil core from Brown Creek, WI, inoculated with one of four earthworm biomasses (0, 3, 7, or 15 g·m^-2).  Cores were watered every third day for 36 days and the leachate was slowly dripped into each paired stream.  We measured major nutrients in leachate and stream water and periphyton growth in the streams.  The total mass of NH₄⁺-N, NO₃^--N, and TN leaching from the soil cores was positively related to earthworm biomass.  Periphyton AFDM and chlorophyll a increased through time but did not differ significantly across earthworm treatments.  Through time, P concentration in the streams declined to <2 μg·L^-1 and periphyton in all streams was highly P-limited and did not assimilate excess N.  This study suggests that riparian zones containing invasive earthworms can function as nitrogen sources, rather than sinks.