Intraarterial blood pressure is measured noninvasively by an electromechanical transducer (22) that includes an array of transducer elements (22-1 through 22-19). The transducer extends across an artery (24) with transducer elements at the ends of the array extending beyond opposite edges of the artery. A set of diastolic and/or systolic pressure and pulse amplitude values is obtained from the outputs from the transducer elements, which values are stored in computer (62). Information concerning the subject related to the diameter of the underlying artery including, for example, the subject's age, weight, arm and wrist diameter also is entered into computer (62) through keyboard (64), from which information an estimation of the diameter of the underlying artery is obtained. Using the set of pulse amplitude values, a transducer element at the center of a search area located substantially at the center of the artery is identified. A center of gravity, a two humps and/or a curve fitting method may be used to identify the transducer element at the center of the search area. A group of transducer elements that overlies the artery of estimated diameter then is identified. Using outputs from only said group of transducer elements, one transducer element having a local minimum of one of the diastolic and systolic pressures, relative to the transducer at the center of the search area, is identified, which transducer element is selected for monitoring blood pressure.