Sustained elevations of blood pressure (BP) are associated with increased risk of cardiovascular morbidity and mortality, so it is important that the condition be managed effectively. However, the rapid responsiveness of BP to environmental changes makes it difficult for the physician to monitor the effectiveness of therapy using office measurements only. Regular self-monitoring is a practical method for sampling a patient's BP in a variety of circumstances (before and after taking medication, home vs. work, etc. ), and self-monitoring has been associated with reductions in BP. Microcomputers enable the physician to condense patient-supplied BP data into tabular and graphic forms useful for patient education and for improving compliance with treatment. Thus, patient-supplied BP data can be simply and economically used to aid BP management in a primary care office practice.