To examine the relative cost-effectiveness of single versus multiple patient education strategies to reduce hypertension, we assigned patients to seven intervention groups and to a usual-care control group using a randomized factorial design. We compared cost-effectiveness measures for single, double, and triple combinations of (a) a clinic exit interview with patients to clarify their medical regimens, (b) an educational meeting with a member of the patient's family to aid in management at home, and (c) a series of small group sessions to help patients overcome personal barriers to management. We observed consistent results for six different effectiveness measures under a variety of decision-making rules. Our results suggest that in the absence of targeting of multiple interventions to systematically selected high-risk patients, multiple intervention combinations are not more cost-effective than single interventions.