The magnetic resonance images (MRI) of 30 patients with surgically or biochemically confirmed pituitary adenomas (20 macroadenomas, 10 microadenomas) were retrospectively evaluated. Ten patients had hyperprolactinemia, another eight had acromegaly, another eight had nonfunctioning adenomal and four had Cushing disease. The examinations were performed at a 1.5-T superconducting MR system using a multisection spin-echo technique with 3mm-thick sections and a 256x224 matrix. T1 weighted sagittal and coronal images were obtained before and within 30 minutes after the administration of Gd-DTPA (0.1mmol/kg) Analysis of the MRI was focused on the signal intensity and enhamcement patterns of the pituitary adenoma before and after Gd-DTPA administration. Compared with endocrinologic diagnosis, macroadenoma showed heterogeneous enhacement in 55%, rim enhancement in 35% and homogeneous enhancement in 10%, Conclusively, the enhancement patterns of the pituitary adenoma did not correlate with the subtypes made according to hormone production.