The aim of this study was to determine if methane emissions from young farmed deer increase with age. Methane emissions of 20 red deer stags grazing permanent perennial rye grass-based pasture were measured four times post-weaning, at 4.5, 6.5, 9 and 11.5 months of age, using the sulphur hexafluoride technique. Methane production and methane yield increased with age (P<0.05) and appeared lower (26%) than previous measurements from adult deer on similar pasture. These results imply that total methane emissions from young deer recorded in the New Zealand Greenhouse Gas Inventory are likely to be overestimated if values are based on adult methane emissions only.