One obvious threat to the endangered arctic fox Vulpes lagopus population in Fennoscandia is competition with the larger red fox Vulpes vulpes, which may have expanded its range towards the alpine tundra because of increased food availability in the low-alpine and subalpine region. The steady increase in the number of vacation cabins and roads, and thus also in human garbage and road-killed animals, may subsidise easily available food resources and improve red fox survival in these otherwise marginal areas. In Børgefjell National Park, Norway, 14 of 27 known arctic fox dens were used by arctic fox during 2001-2005. The dens that were used were situated at higher altitudes, farther from natural red fox habitats, than unused dens. In the best of our logistic regression models, there was also a statistical negative effect of the number of cabins within 7 3 7 km squares around the den sites. Hence, our results support the prediction that the arctic fox is less likely to use areas where human activity might be benefiting red foxes. A successful conservation strategy for the arctic fox will probably require a reduction of the driving forces behind the red fox expansion in the alpine areas.