PURPOSE AND METHODS: High-field MR images at 1.5 T were used to characterize the effects of age and gender on pituitary size and shape in a sample of 71 adult volunteers (40 females), aged 21 to 82 years. FINDINGS: For all subjects, age was inversely correlated with pituitary height (r = -.43, P less than .0002) and cross-sectional area (r = -.35, P less than .0028). Age-specific gender differences were also present in pituitary height and area. A convex upper pituitary margin was more common in females (P = .002) and younger subjects (P = .009). CONCLUSIONS: This study confirms that aging is accompanied by gender-specific changes in pituitary size and shape, and provides normative data that may facilitate evaluation of the pituitary gland in neuroendocrine disorders.