To investigate the possibie difference, if any, between office blood pressure(BP) and home BP may be important in the diagnosis and treatment of hypersensive patients. This report deails the difference between the two BP's and the usefulness of digital electronic sphygmomanometer(DES) for self-monitoring of home BP.

The BP's of 14 patients with essential hypertension were measured with mercury sphygmomanometers at outpatient department by physician and with DES at home(twice a day) by the patients. Patients were followed up every 2 weeks for 4 weeks and previous 2 weeks' average home BP's were compared with the office BP's of each 2 weeks' end.

There was a significant difference between office and home BP(both systolic and diastolic) ; office average BP(151/95mmHg) was higher than home average BP(136/86mmHg).

Caution may be needed in the interpretation of office BP unless it is measured several times after adequate rest.