We carried out a cross-sectional study to define the prevalence of ulnar nerve instability and its relationship to ligamentous laxity in the pediatric population. Children were divided into three age groups: group I (0-5 years), group II (6-10 years), and group III (11-18 years). Of children in group I 17.7%, of children in group II 7.7%, and 5.7% of children in group III had dislocating ulnar nerves. With the exception of one patient, nerve instability was bilateral. Of those children possessing all five Wynne-Davies signs of ligamentous laxity, 25.4% had dislocating nerves, 71.9% had subluxing nerves, and 2.6% had stable nerves. Age, ulnar nerve instability, and ligamentous laxity were statistically associated (p < 0.0001).