Growth at puberty is an important component of normal linear growth. The adolescent growth spurt (AGS) is the result of a critical concentration of sex steroids combining with pituitary growth hormone to increase the growth rate from a prepubertal value of about 4 cm/year to 8–10 cm/year. The growth rate then decreases until growth is complete. The endocrine influences of pubertal growth are sex steroids, growth hormone and possibly insulin, all of which increase during puberty. Pubertal growth, together with general body maturation is significantly delayed in chronic paediatric illness such as Crohn’s disease or cystic fibrosis. This may cause psychological disturbance as may simple or constitutional growth delay. The most appropriate therapy for growth delay is androgens in the form of testosterone or HCG injections.