The sella MRIand CT of 11 patients with primary pituitary dwarfism (PPD) were evaluated in this study. The results revealed that MRI could find the aplasia of the pituitary and the abnormality of the pituitary stalk and pituitary posterior lobe, while CT only could show the disapperance of the pituitary and not the morphology of the pituitary and its posterior lobe. The CT scanning of the pituitary stalk was less clear than that of MRI. It is suggested that MRI has better tissue contrast and sensitivity, especially to the display of slight structure. Besides, the sella abnormality in MRI provides an important morphological basis for diagnosis and treatment of PPD.