Neurological endemic cretinism, resulting from severe iodine deficiency, is characterized by mental deficiency, deafmutism, and a spastic-rigid motor disorder. Its neuropathology and pathophysiology have been investigated very little. We report the clinical and magnetic resonance imaging brain scan findings of 3 adult Chinese cretins. All show an apparent magnetic resonance imaging abnormality in the globus pallidus and substantia nigra, with hyperintensity on T1-weighted images and hypointensity on T2-weighted images. The motor abnormality, characterized by truncal and proximal limb-girdle rigidity and spasticity, with relative sparing of the hands and feet, is analogous to other extrapyramidal disorders. Endemic cretinism is a unique form of cerebral palsy of potential interest for students of human neuromotor development.