Monthly increments of length, weight gain, and head circumference were recorded from birth to 4 years of age in 52 children with cystic fibrosis. At birth the children showed stunting. Standard deviation (SD) scores at birth for height, weight, and head circumference were -1.24, -0.72, and -1.82 respectively. Over the first four years, length and weight SD scores showed a consistent improvement. However, there was very limited improvement in head circumference, which stabilised 1 SD below the mean from 1.5 years to 4 years. Our data suggest that head growth lags behind gain in height and weight in children with cystic fibrosis despite good nutritional management in early infancy. The data may also support the expression of cystic fibrosis transmembrane conductance regulator in choroid plexus and ependyma.