Thredbo Village is a year round alpine resort located in Kosciusko National Park, south eastern New South Wales. Treated sewage effluent from Thredbo Village is discharged to the upper Thredbo River. The river is a rocky bottomed, high mountain stream (> 1,200 m altitude in the study area) flowing predominantly through subalpine woodland, the only major impact on the river within the study area was that of the Thredbo Village alpine ski resort. Nutrient concentrations were measured in the upper Thredbo River monthly from January to September 1983 at 9 sites along the river, both upstream and downstream of the effluent discharge. In addition, invertebrates were collected at the same sites in January, April and July 1983. The near pristine section of the upper Thredbo River upstream of Thredbo Village was low in phosphorus and nitrogen (<20 mg m-3 and <100 mg m-3 respectively). The sewage effluent discharge was high in phosphorus and nitrogen (up to 5,000 mg m-3 and 28,000 mg m-3 respectively). Phosphorus generally returned to concentrations similar to those measured in the pristine sections by 3.5 kilometres downstream of the discharge. Nitrogen (mostly in the form of nitrate and nitrite) often remained elevated down to the most downstream site, 8 kilometres downstream of the effluent discharge. The elevated nutrient concentrations immediately downstream of the effluent discharge stimulated the growth of attached filamentous algae in January when conditions for growth were most favourable. It is concluded that this growth provided an additional food source for several invertebrate taxa, Cricolopus sp. 12E and 160E (Diptera, Chironomidae), Conoesucidae sp. TR6, Oxyethira columba (Trichoptera), Nais sp., Aeolosomatus niveum (Oligochaeta), and Austrocercella tillyardi (Plecoptera), which occurred in higher numbers downstream of the effluent discharge. Downstream of the effluent discharge the taxonomic composition of the invertebrate community was not altered substantially from that upstream, although there was a significant increase in the abundance of the taxa which could take advantage of the increased food resource. The changes in the invertebrate community were not evident 3.5 kilometres downstream of the effluent discharge, which corresponded to the return of phosphorus concentrations to background levels. There were increased abundances of several invertebrate taxa downstream of both Thredbo Village and the rubbish tip in January which were consistent with, but not as great as, those downstream of the sewage effluent discharge. This was likely to be a result of increased nutrient loads from urban runoff and tip leachate at these sites which possibly lead to increased algal productivity. However, nutrient concentrations at these sites were not notably higher than at the control site. The sewage effluent discharge resulted in only small changes to the invertebrate community in April or July 1983.