Nutrient status of freshwater ecosystems has a significant influence on biological invasions, species richness and community structure. The role of phosphorus in driving these effects has been widely reported while that of nitrogen is being increasingly considered. In a glasshouse experiment, we investigated the growth responses of two invasive exotic (Egeria densa and Salvinia molesta) and one native (Vallisneria spiralis) macrophyte species to additional low concentrations of nitrogen (NO3-N). The species were grown across five levels of low nitrogen treatments (0.02, 0.05, 0.1, 0.5, and 0.9 mg NO3-NL-1). We hypothesised that the invasive exotic species will produce more biomass in the higher range of tested nitrogen concentrations while V. spiralis growth will be favoured in the lower ranges. The invasive E. densa growth responded positively to increasing nitrogen concentration as hypothesised. Contrary to our hypothesis, V. spiralis produced more biomass in the higher nitrogen treatments, and biomass production of S. molesta was more favoured by the mid-range nitrogen concentrations of 0.05 – 0.1 mg NO3-NL-1. We conclude that increasing N at these low concentrations results in greater growth for E. densa and V. spiralis, but S. molesta growth is less strongly linked to N concentration.