Human growth hormone (HGH) secretion was assessed in 47 consecutive patients with pituitary disease and was compared to the secretion of other pituitary hormones. Nine patients had acromegaly and HGH hypersecretion, two had adrenocorticotropic hormone hypersecretion and Cushing syndrome, and two had nonpuerperal galactorrhea (prolactin hypersecretion). Twenty-nine patients had HGH deficiency, 21 had follicle-stimulating hormone—luteinizing hormone deficiency, 15 had thyroid-stimulating hormone deficiency, and 10 had adrenocorticotropic hormone deficiency. Abnormal HGH secretion appears to be the most frequent endocrine dysfunction among patients with pituitary disease.