We examined growth patterns by age and sex in 133 children and adolescents with sickle cell disease. These patients are estimated to be representative of the total population aged 1 to 18 years with sickle cell disease in a large metropolitan area. Median height and weight curves constructed from serial growth data available for all 133 children demonstrated impairment in height and weight at all ages and in both sexes. Analysis of growth trends by age reveals a pattern of increasing deficit with increasing age; boys are more severely affected than girls. Growth velocity curves constructed for a series of 13 adolescents with sickle cell disease illustrate the marked delay in the onset of the normal pubertal growth spurt in these patients.