Aim: To evaluate longitudinal growth in 21-hydroxylase deficiency congenital adrenal hyperplasia (CAH), factors contributing to this and outcome for BMI, weight (Wt) and height (Ht) in adolescence. Methods: Multi-level longitudinal models were used to evaluate growth patterns of 45 salt wasters (SW) and 12 non-SW with CAH. Results: Ht, Wt and BMI growth curves differed between SW and non-SW, and by gender. In contrast to SW and males, non-SW females showed a markedly different pattern with a progressive increase in Wt and BMI SDS over childhood and adolescence and only a slight gain in Ht SDS. BMI SDS remained above 0 after early childhood. Over the 15 years, the growth variables were negatively associated with fludrocortisone (FC) (shorter children were receiving larger doses) but not hydrocortisone (HC) doses nor FC and HC doses in the first year. Conclusion: The growth patterns in these children with CAH were influenced by age, gender, phenotype and FC treatment. There was a trend to increasing BMI from an early age, greater adiposity during childhood and females had disproportionately greater adiposity but shorter stature during adolescence. These patients therefore have a predisposition to obesity in childhood and later life independent of early corticosteroid treatment. Copyright © 2010 S. Karger AG.