In the initial assessment of mild hypertensive patients a prolonged period of repeated measurement is necessary to ensure accurate diagnosis. Home monitoring of blood pressure (BP) may accurately predict those patients whose hypertension will be 'sustained' in a clinic environment and it is important therefore to establish whether average home BP is stable on repeated assessment. Seventeen patients found to be hypertensive on screening were recalled after two weeks and again after four weeks for further BP measurement. All patients monitored home BP over 3 days following each clinic visit. Clinic BP fell from the first to last visit (181 +/- 4/97 +/- to 162 +/- 5/93 +/- 2 mmHg, P less than 0.05) with no change in home BP over the same period (153 +/- 3/89 +/- 3 to 154 +/- 4/89 +/- 3 mmHg). It is clear therefore that an average home BP produced during three days of monitoring is a stable measurement at least over a four week period and thus in the initial assessment of a hypertensive patient this technique may allow for greater diagnostic accuracy.