We describe a simple bedside procedure (which we call "Osler's maneuver") that differentiates patients with true hypertension from those whose blood pressure is spuriously elevated because of excessive sclerosis of the large arteries ("pseudohypertension"). The maneuver is performed by assessing the palpability of the pulseless radial or brachial artery distal to a point of occlusion of the artery manually or by cuff pressure. We classified 24 elderly hypertensive patients as either Osler-positive (n = 13) or Osler-negative (n = 11), and measured their intraarterial pressure, arterial compliance, and systemic hemodynamics. Patients with pseudohypertension (Osler-positive) had falsely elevated blood-pressure readings, with a difference of 10 to 54 mm Hg between cuff and intraarterial pressure. Arterial compliance was lower in Osler-positive subjects and correlated with the difference between cuff and intraarterial pressures, indicating that the stiffer the artery, the more pronounced the degree of pseudohypertension. Pseudohypertension is common in the elderly and becomes more severe as arterial compliance decreases and sclerosis of large arteries progresses.