Energy metabolism of the roe deer Capreolus capreolus (Linnaeus, 1758) was investigated by means of the respirometric method. The level of metabolism in roe deer is similar to that of other wild ruminants but higher than the mean interspecies metabolism of mammals. Fasting heat production (FHP) shows seasonal variations, being the highest during spring molting season, slightly lower in summer and the lowest in winter: 117.0, 99.4 and 91.3 kcalXkg-o-^Xday-i, respectively. In spring and summer the metabolism increases at lower temperatures: FHP (kcalXkg-0- 75Xday-i) = 181.5—5.32 t (where t=°C). Resting metabolism of non-fasted animals (RHP) is higher than FHP by 25—30%, and this difference represents the specific dynamic action of food (SDA). Motoric activity causes a rise of metabolism by 9—210°/o, the cost of maintaining of upright position being equal to 1.1 kcalXkg-0-75X Xhr-i. Resting metabolism of fawns up to 80 days of life is linearly correlated with their body weight (W, kg): RHP = 73.53W (where RHP = =kcalX animal -1 X day - 1 ). RHP reaches the highest values on 7th day of life. In fawns 6 to 8 month old FHP amounts to 109.9 kcalXkg-°-75X Xday -1 , and RHP is higher by 22%. The mean respiratory quotient (R.Q.) was equal to 0.82; the lowest values (0.79) were observed in fasting and resting animals, while the highest (0.86) in active nonfasting ones.