A computerized system has been developed which potentially enables a single expert physician to monitor a large number of hypertensive patients being seen at distant locations. The patients may receive their care directly from primary care physicians or nurse-physician surrogates. Primary care physicians can use the same data bank to monitor their own panels of patients. These goals are accomplished through a special purpose, interactive programming language which can be used to perform sophisticated data retrieval along different complexes of parameters. The physician is able to query the computer, via a terminal, about any group of patients he defines and have displayed to him the clinical data requested. The system is open-ended, enabling one query to lead to another.Four hundred and ninety-three patients have been entered into this program so far, including 29 patients with diastolic pressures greater than 115, 92 with diastolic pressures of 104 to 114, and 372 with diastolics of 90 to 104. Among patients who have been on therapy for at least six weeks, 80 per cent were at goal blood pressure. Ten to 14 weeks after therapy was initiated, 69 per cent of all patients in the program were at goal blood pressure.The system provides a useful means of monitoring a large hypertensive population of patients. Such a system can result in a more efficient utilization of medical personnel and can bring the consultative services of highly trained specialists to larger segments of the population.