The aim of this study was to examine the value of deer carcass measurements as indices of population 'well-being' and to-determine how best they could be applied to the management of red deer. It was based on three samples (totalling 4200 animals) of carcass measurements from red deer killed in commercial helicopter hunting operations in the high country of South Westland, New Zealand. The samples were collected at three year intervals spanning a period when deer numbers were being rapidly reduced by hunting. These data were subsequently divided into three populations on the basis of geographic areas and time of colonisation. Four groups of measurements were investigated, those of skeletal size, body weight, body fatness, and female reproductive performance. These were treated separately with the same general objectives, which were; (a) to describe the various methods of measurement, their characteristics and relative merits; (b) to investigate the relationships (in selected measures only) between sex, age, and season to find the most practical way of comparing samples of animals; and (c) to compare the differences between, and changes in, the study populations of deer to test the value of the skeletal measures. It was concluded that the best estimate of deer population 'well-being' would be obtained using a combination of measurements including one each of physical size, body "condition", and reproductive performance. The methods considered most appropriate for this purpose were a jaw length index of skeletal size, a carcass weight-for-size index of "condition" (both methods have been described in detail), and the proportions of females either pregnant or lactating. The general application of these methods has been discussed and the need for further work suggested.