Chlorpromazine is frequently administered to patients with hyperprolactinemia to stimulate an increase in the serum levels of prolactin. A patient with a prolactin secreting adenoma is described in whom pituitary apoplexy developed in association with a hypotensive episode following the administration of 25 mg of chlorpromazine. Prolactin levels fell from more than 2,000 ng/ml to 340 ng/ml following infarction of the pituitary tumor. Pituitary apoplexy should be considered as a rare complication of chlorpromazine stimulation in a patient with a pituitary tumor.