Linear growth and sexual maturation were assessed in 68 long-term pediatric renal allograft recipients (43 boys) receiving daily or alternate-day prednisone therapy. Growth was analyzed both during the prepubertal period and during puberty. Height at transplantation was greater than 2 SD below the mean in 34.2% of prepubertal children. After the first posttransplant year, 59.2% of the prepubertal children had a normal height increment (greater than 4.8 cm/yr). Onset of puberty was recorded at a chronologic age of 14.6 +/- 1.9 years in boys and 13.3 +/- 1.9 years in girls. Height at onset of puberty related to chronologic age was -2.4 +/- 1.3 SD. Height velocity during puberty was within normal limits in 62.5% of the children. No significant difference in pubertal growth was detected in patients who had received transplants before and after the onset of puberty. Duration of pubertal development was within normal limits. In girls, menarche was achieved at a mean chronologic age of 15.9 years and bone age 12.9 years. Adult height was attained at an average age of 20.3 years in boys and 18.7 years in girls. Overall, one third of the children attained an adult height greater than 2 SD below the mean. Our data indicate that although poor growth before kidney transplantation has a great influence on adult height, the loss of growth potential during pubertal development seems even more important.