These data are serum urea nitrogen and creatinine levels for polar bears captured in the southern Beaufort Sea 1983-2016 and the Chukchi Sea 1987-1993 and 2008-2017. The dataset includes relevant information about the bears that were captured including the latitude and longitude of their capture location, capture date, age class and sex, the age and number of cubs accompanying an adult female, and whether the bear denned during the previous winter or exhibited signs of being engaged in mating behavior at the time of or just prior to capture.