Changes in milk composition (total solids, carbohydrate, protein, lipid and calculated gross energy content) during lactation in three groups of wild (recently culled) and one captive group (fed ad libitum) of Tasmanian pademelon (Thylogale billardierii) were related to growth rates and body condition. The habitats of the three wild groups differed. Total milk solids were generally greater in the captive group but this difference disappeared in late lactation. Milk carbohydrates showed a general increase to mid-lactation in all groups, decreasing subsequently, but were always greater in the captive group. The captive group’s milk protein was always greater than those of wild Groups 1 and 2 but differed from wild Group 3 only in mid-lactation. Milk lipid concentrations started low in all groups; thereafter, the captive group had higher concentrations of lipid in mid-lactation but there were considerable differences between the groups in late lactation with Group 2 having the highest concentrations. Other than in the captive group there was little difference in energy content between early and mid-lactation. Growth rates of young differed between all wild groups, with the captive population exhibiting more rapid growth than all others. Thus, differences in milk composition resulting from different planes of nutrition can lead to differences in growth rates of marsupial young.