The Swedish moose population has during the last 60 years been going through rather drastic changes in numbers. Recently there also seemed to have been a shift towards males with less and less developed antlers, which is an important problem for the moose population breeding. The aim with the present study was to study how antler size in the moose is related to age, body mass and population density. Information on the antler and body mass characters was obtained from 425 males that were shot during the annual moose hunting in October between the years 1999-2006. Age and body mass were the variables that explained most of the variation in antler size in this study. A residual of antler points over age, demonstrated a positive correlation between residuals and carcass, such that males with larger antlers for their age, was on average heavier than other males. There was also a significant negative correlation between population density and carcass. The high mortality rate of older males have lead to that few males reach an age where the horns are fully developed and the age distribution has moved to younger ages. As a consequence of this fact the males start to reproduce at younger ages. As the rutting behaviour is a very energy demanding activity, the younger male’s body growth will be constrained and there will be a large cost to come in rutting stage early. As the percentage of males and male age is having an impact on the reproduction of the population, this is an important problem which should be considered in order to give the right prerequisites for a more productive population of moose with big males that have well developed horns.