Due to observed interactions between Svalbard reindeer (Rangifer tarandus platyrhynchus) and polar bears (Ursus maritimus) during field work on Edgeøya, Svalbard, we measured response distances for reindeer from a stalking polar bear and improvised five approaches from a person disguised as a polar bear for comparison with human encounters. The alert, flight initiation and escape distances were 1.6, 2.5 and 2.3 times longer, respectively, when Svalbard reindeer were encountered by a person disguised as a polar bear compared to a person in dark hiking gear. Population increase of polar bears on Svalbard and decrease in sea-ice cover in the Arctic region during summer probably results in more frequent interactions with reindeer on the archipelago. Similar reindeer response behavior from encounters with a polar bear and persons disguised as polar bears indicate a predator-prey relationship between the two species on Edgeøya.