Growth in the first year of life was studied prospectively, at monthly intervals, in 49 Aboriginal babies born into 6 remote communities in the tropical north-west of Australia. Birthweights, on average, were slightly lower than international (NCHS) reference values but growth velocity in the first 3 months of life exceeded international reference values. After that, growth rates in Aboriginal infants slowed and their attained weights and lengths fell behind expected values for age. By 12 months of age the Kimberley boys were 1.35 kg lighter and 4 cm shorter than the NCHS values while the Kimberley girls were 1.04 kg and 2.8 cm less than the international reference values. Environmental factors are considered dominant in determining these growth patterns in Australian Aboriginal infants.