Acute lymphoblastic leukemia (ALL) is the commonest childhood malignancy in Australian children. Recently published data from Western Australia suggest a link between proportion of optimal birth weight and the risk of ALL, but few studies have investigated the relationship between growth during infancy and early childhood and risk of leukemia. The aim of this study was to determine whether children diagnosed with ALL in Western Australia were taller at the time of diagnosis than children of the same age and sex in the general population.