Much recent research has focused on understanding the environmental factors that limit the distribution and abundance of species. However, by no means all models consider the effects of interspecific competition on species' distributions. In this study, we explore the contribution of both environmental factors and the presence of another ungulate species on the distribution of two sympatric deer species: roe deer (Capreolus capreolus) and red deer (Cervus elaphus). To assess the importance of both biotic and abiotic factors, we constructed models for each species incorporating environmental predictors and an index of abundance of the other species. High density of shrubs and distance to roads had a positive affect on roe deer occurrence while spatial heterogeneity, namely mean shape index, and the presence of red deer had a negative effect. In contrast, the percentage of shrub cover, landscape heterogeneity and the presence of roe deer all positively affected red deer occurrence. Our results suggest that interspecific competition between these species might occur with asymmetric effects and underlines the need to explore the nature of these interactions in greater detail in southern ecosystems. © Koninklijke Brill NV, Leiden, 2012.