Prader-Willi syndrome (PWS), a genetic disorder due to an alteration in the paternally derived long arm of chromosome 15, is characterized by a complex clinical picture (short stature, obesity, hypogonadism) that seems to be referable to as a central hypothalamic/pituitary dysfunction. To determine whether there is any diminution in the anterior pituitary gland or other neuroradiological alterations, we retrospectively analysed 91 patients with PWS (42 females, 49 males; age range: 0.7-16.8 years) by cerebral magnetic resonance imaging (MRI). Of these 91 patients, MRI analysis showed a reduction in pituitary height in 45 patients (49.4%), a complete absence of the posterior pituitary bright spot in six patients (6.6%) and other neuroradiological alterations in ten patients (11%). Altogether, neuroradiological alterations were present in 61 of the 91 (67%) patients. Our results indicate that neuroradiological alterations are more frequent in PWS patients than has been reported to date.