The majority of patients presenting for resection of phaeochromocytoma require some form of antihypertensive therapy during operation. Phentolamine and sodium nitroprusside have both been used successfully for this purpose, but each has disadvantages. This report describes the use of intravenous nitroglycerin, a rapidly acting venodilator with no appreciable toxicity, as the sole antihypertensive agent in two patients with phaeochromocytoma and partial alpha adrenergic blockade. Hypertensive episodes were quickly and effectively controlled in each case. There were no hypotensive periods and no side effects.