Weighing large animals in the field is often labourious and expensive. Alternative methods which replace direct measurements of body mass are, therefore, of practical value. In order to predict body mass in moose Alces alces, an allometric model based on chest circumference, sex, age and population was applied. A model to predict body mass based on chest circumference and a truncated age measurement is suggested. Impact of sex and population was weak. The ability to predict body mass was mostly influenced by chest circumference. The proportion of carcass mass to total body mass varied between 45% and 51 % among age-classes. In addition, there was a slight effect of sex on this variation, males having a proportionally larger carcass mass than females. The model's predictions of body mass are adequate for describing the distribution of body mass in moose populations and for comparing moose populations.