Fluctuating asymmetry (FA) of foramina as a measure of environmental stress was studied in polar bear (Ursus maritimus) skulls from East Greenland (n = 300, collected 1892–2004) and Svalbard (n = 388, collected 1950–2004). Levels of FA for each of the 11 traits used in the study were compared between sex/age groups (subadults, adult females, adult males), localities (East Greenland, Svalbard), and periods (≤ 1960 [prepollution] and > 1960, [pollution]) using general linear models (GLMs). The GLMs revealed that adult males had higher FA in two traits than other sex/age groups. Also, the Svalbard bears had higher FA in number of intracondylar foramina than had those from East Greenland, a trend corresponding well with skull differences found previously between the two subpopulations. No correlation was found between the bears' year of birth (n = 468) and FA or between levels of contaminants and FA (n = 65).