We report on anthropogenic waste ingestion and associated foreign-body gastric pathology in polar bears (Ursus maritimus) within the North Slope Borough, Alaska, from stomach content analysis of 42 bears during 2010 to 2020. User plastics and rubbish other than plastics were observed in 28.6% (12/42) and 11.9% (5/42), respectively. Acute gastritis was present in 33.3% (14/42) of polar bear stomachs. Fifty percent of the acute gastritis cases (n = 7) were observed in animals with user plastics in their stomach content. The findings of our multiyear polar bear stomach-content analysis emphasize that anthropogenic waste ingestion is common in polar bears of the Southern Beaufort Sea subpopulation. For the future, controlling access to anthropogenic foods (e.g., garbage dumps, stored wildlife resources) will be an important component of proactive human polar bear management on the North Slope, Alaska, and for the entire Arctic.