During a 10-year period, 23 girls compared to 118 boys presented with constitutional delay in growth and puberty. Of these girls, 15 were followed to final height to determine the outcome of the untreated condition in terms of both growth and psychological well-being. At presentation chronological age was 13.2 (1.7) years [mean (S.D.)], bone age delay 2.7 (0.9) years, standing height standard deviation score (SDS) -3.4 (0.9), and predicted adult height (PAH) SDS -1.3 (0.7) (Tanner-Whitehouse II method). Final height SDS was -1.5 (0.8) measured at 18.9 (2.6) years of age. Mean age at menarche was 15.6 (0.9) years. There was no significant difference between final adult height (FH) and PAH but there was a significant difference between FH and target height (P less than 0.001). Psychological questionnaires revealed no significant difference in self-esteem, marital or employment status between the patient and control groups. There was no significant correlation between self-esteem and FH but 80% felt their growth delay had affected success either at school, work or socially. Of the patients, 50% would have preferred treatment to advance their growth spurt. This study demonstrates that girls with constitutional delay in growth and puberty reached their PAH, although this was lower than the midparental heights. The girls also experienced significant distress due to delayed growth and puberty and treatment to advance growth should be considered more frequently.