Abstract: A non-invasive system and method for measuring blood pressure variability includes a cuff (20) pneumatically connected to a pump (14) to inflate the cuff to be wrapped around a limb (21) of a subject. A pressure sensor (18) is associated with the cuff for measuring cuff pressure (52). A photoplethysmogram sensor (26) attached to a fingertip in the same limb (21) of the subject and placed distal to the cuff for monitoring blood flow and recording a pulse plethysmograph signal. A control unit (12) connected to the pressure sensor (18) and the photoplethysmogram sensor (26) for simultaneously recording the cuff pressure and the plethysmograph signal such that an empirical relationship is derived between the cuff pressure and an amplitude measure of the plethysmograph signal (54) to measure short-term variation in systolic and diastolic blood pressures at a frequency corresponding to respiratory cycle.