Some results of a study of techniques for the noninvasive and ambulatory measurement of blood pressure are presented. A method for computer processing ambulatory or stress test data to determine blood pressure is described. It appears that good accuracies can be obtained with ambulatory patients during normal ranges of physical activities and perhaps during treadmill tests. The development and testing of a new transducer for the noninvasive beat-by-beat measurement of blood pressure is described. The transducer outputs are similar to intraarterial wave-forms that are obtained by catheter, and it is expected that the transducer will be used in the operating room, the ICU, and the CCU.