Fat content in femur marrow was analyzed by the dry-weight method from 181 Alaskan moose (Alces alces). Samples were classified as adults or calves, cause of death and month sampled. Marrow fat values from adults killed by wolves (Canis lupus) or by various accidental means (road-kill, shot and drug) were not significantly different from each other, but both were significantly higher than those from suspected starved moose. Marrow fat values from wolf-killed calves were not significantly different from those of calves dying accidentally; they were significantly higher than those of suspected winter-killed (starved) calves. Marrow fat values from suspected winter-kills were above 10%. Wolves were not selective for moose with marrow fat values below 10%, but took both cows and calves with marrow fat means not significantly different from accidental mortalities. The effect of severity of winter on fat values is discussed. Femur marrow fat values provide a method for comparing mortality factors and a means of identifying winter-killed (starved) moose.