We assessed habitat selection patterns of the European bison (Bison bonasus) reintroduced to the Bieszczady Mountains (the Eastern Carpathians, Poland) using presence data and Ecological Niche Factor Analysis. During the growing season, bison selected habitats at higher elevations close to natural grasslands, coniferous forest, and stands with broken canopy, while in winter — lower elevations, close to agricultural areas and alder or pine stands. In both seasons, bison avoided busy roads. The use of low-elevation valleys in winter can be a trade-off between the access to good habitats with milder climate, and the risk associated with close proximity to people. Relative tolerance to proximity to infrastructure indicates that good quality habitats in its vicinity can be considered suitable for further expansion of the species' range. Optimal sites for bison introductions in the Carpathians should include areas at lower elevations, providing winter refuges, and allow unrestricted access to summer habitats at higher elevations.