Objective: To measure the delays in diagnosis of Turner’s syndrome (TS) and to propose strategies for earlier screening and diagnosis. Methods: The medical records of 81 girls with TS were reviewed for age at diagnosis, reason(s) for karyotype analysis, and clinical features including growth failure. Delay in diagnosis was calculated as equal to age at diagnosis for children born with lymphedema and/or 2 or more of the following dysmorphic features: webbed neck, nail dysplasia, high palate, and short fourth metacarpal. For all others, delay in diagnosis was calculated as the difference between the age at which height fell below the 5th percentile and the age at which the diagnosis of TS was made. Results: Lymphedema was the key to diagnosis in 97% of the girls diagnosed with TS in infancy, and short stature was the key to diagnosis for 82% of the girls diagnosed in childhood or adolescence. For girls diagnosed in childhood or adolescence, the delay in diagnosis averaged 7.7 ± 5.4 years. Many had dysmorphic features and/or a history of lymphedema at birth, and diagnosis was made an average of 5.3 years after patients had fallen below the 5th percentile for height. By the time of diagnosis, patients were very short, averaging –2.9 SD in height. Conclusions: The diagnosis of TS is often delayed. We recommend karyotype analysis for all girls with unexplained short stature, delayed puberty, webbed neck, lymphedema, or coarctation of the aorta. Furthermore, karyotype analysis should be strongly considered for those who remain above the 5th percentile for height but have 2 or more features of TS, including high palate, nail dysplasia, short fourth metacarpal, and strabismus. (J Pediatr 2000;137:455-9)