The objectives were to describe the clinical features of pediatric patients with abnormal posterior pituitary glands, either ectopic or absent on MR images, and to note any associated anomalies. MR images of eighteen patients with abnormal posterior pituitary glands, age range 7 months to 16.5 years, were reviewed. Their clinical features, pituitary glands, pituitary stalks, optic tracts/chiasms, and midline structures were studied. The clinical features were polyuria/polydipsia (8), short stature (6), congenital blindness (2), previous head injury with hypoglycemic shock (1), and right microphthalmia with delayed development (1). MR images of the patients with polyuria/polydipsia showed absence of the posterior pituitary gland in all, thickening of the stalk in 1, empty sella in 1, and absence of the septum pellucidum and thinning of the corpus callosum in 1. MR images of the patients with short stature showed absence of the posterior pituitary gland in 3, ectopic posterior pituitary gland in 3, a small anterior pituitary gland in 5, and absence of the septum pellucidum in 3. MR images of the patients with hypoplasia of the optic nerves showed ectopic posterior pituitary glands, small optic tracts, and abnormal corpora callosum. Clinical features of patients with abnormal posterior pituitary glands varied. Most presented with symptoms of pituitary hormone deficiency, some with orbital anomalies. Other midline brain anomalies of the brain were often seen.