Short stature is a very common manifestation of Noonan syndrome (NS) and is accompanied by a variable delay in bone age. Although reports of adult height in NS are uncommon, some feel growth hormone therapy will increase adult height. We report our findings in 73 adults over 21 years of age with NS. Thirty percent of this group had an adult height in the normal range between 10th percentile and 90th percentile. Over half of the females and nearly 40% of males had an adult height below the 3rd percentile. The presence or severity of heart disease was not a factor, and none of the adults with a normal height had been treated with growth hormone. Serial measurements of height for many years through childhood to adulthood were available in only a few patients, but their pattern of growth suggests catch up may occur in late adolescence. To evaluate the benefit of growth hormone therapy, long term serial height measurements over a period of years comparing treated and untreated patients are needed. It will be important to determine what role, if any, the mutated PTPN 11 gene plays in the short stature common in NS. © 2003 Wiley-Liss, Inc.