True metabolisable energy (TME) of various foodstuffs were determined in turkeys at 3, 9 and 17 weeks of age. 2. TME of soyabean meal did not change with age but TME of wheat and maize was 13% higher in 17-week-old turkeys than in 3- and 9-week-old birds. 3. These differences should be taken into account when formulating diets for turkeys.