To overcome shortcomings in the delivery of care for hypertension various approaches have been developed including a system whereby care of hypertension is shared in a formal manner between general practitioners and hospital specialists. The feasibility, acceptability and cost-effectiveness of a computerised model of shared care were investigated in three matched groups of patients attending hypertension clinics in Glasgow. Glasgow Blood Pressure Clinic attenders considered suitable for shared care by their consultants were randomised to shared care (n = 277) or continued clinic follow-up; a further control group (n = 277) was identified from an independent nurse-practitioner clinic. After 2 years of follow-up, feasibility was estimated by the proportion of patients who had undergone an adequate review (blood pressure, serum creatinine and electrocardiograph); acceptability to general practitioners and patients was assessed by questionnaires; cost-effectiveness was calculated as the cost (to National Health Service and patient) per adequate review. The drop-out rate for shared care over 2 years was 3% compared with 14% for the outpatient clinic and 9% for the nurse-practitioner clinic. In year 2, rates of adequate reviews were 82%, 52% and 75%, respectively. Blood pressure control was similar in the groups. Of 297 general practitioners invited to participate, 85% agreed and 68% wished to continue participation after 2 years. About 50% of shared care patients preferred this method of follow-up compared with their earlier experience of clinic attendance. Shared care was more cost-effective than either conventional or nurse-practitioner clinic follow-up, especially with respect to cost to the patient; costs per adequate review (pound sterling) were 28.96, 50.55 and 30.95, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)