Several computed tomographic scan studies have described empty sellae in children with hypothalamic-pituitary disorders. Magnetic resonance imaging, however, is a more precise technique for visualizing the intrasellar content, such as the stalk and pituitary lobes. Using magnetic resonance imaging, we studied 339 children and adolescents (mean age +/- SD, 12.7 +/- 4.5 yr) with possible hypothalamic-pituitary disorders to ascertain the frequency of primary empty sella and examine its relationships with other intrasellar abnormalities, pituitary function, and adverse perinatal events. One hundred and ninety-three patients had isolated GH deficiency, 43 had multiple pituitary hormone deficiency, 10 had diabetes insipidus, 17 had hypogonadotropic hypogonadism, 5 had idiopathic delayed puberty, 47 had precocious puberty, and 24 had other hypothalamic pituitary disorders of hyperfunction. One tenth (10.9%) of the patients (37 cases) had empty sella, with a marked variation of incidences among the disorders listed above. A statistically higher frequency of subjects with empty sellae was found only in patients with multiple pituitary hormone deficiency. Patients with and without empty sellae were not different in regard to age or sex. The incidence of empty sella in the various groups of patients was as follows: isolated GH deficiency, 8.8% (17 cases); multiple pituitary hormone deficiency, 34.9% (15 cases); hypogonadotropic hypogonadism, 5.9% (1 case); idiopathic delayed puberty, 40% (2 cases); and precocious puberty, 4.2% (2 cases). No patients with isolated diabetes insipidus or other hypothalamic-pituitary disorders had empty sellae. In the patients with empty sellae, abnormalities of the stalk or posterior lobe were found in 1 patient with isolated GH deficiency (5.9%), 13 patients with multiple pituitary hormone deficiency (86.7%), and no patients with puberty disorders. Likewise, adverse perinatal events were found only in 1 patient with isolated GH deficiency and 9 patients with multiple pituitary hormone deficiency. These findings suggest that empty sella is not rare in children and adolescents evaluated for hypothalamic-pituitary disorders, particularly if there is multiple pituitary hormone deficiency. Empty sella can be found regardless of abnormalities of the stalk and posterior lobe, and adverse perinatal events do not seem to be the primary etiological factor. Empty sella is usually associated with pituitary hypofunction, but it can be found in patients with hyperfunction of the hypothalamic-pituitary-gonadal axis.