As more scientific evidence accumulates concerning the relationship between ambulatory blood pressure and hypertensive organ disease, the technique of ambulatory blood pressure monitoring appears to be gaining a foothold in clinical practice and research. Over the past 2 years, an important follow-up study has revealed that 'white coat' hypertension has a low morbidity compared with sustained hypertension. However, other cross-sectional studies continue to fuel the debate regarding the definition and risks associated with white coat hypertension. The application of ambulatory blood pressure monitoring to clinical hypertension trials remains superior to that of office blood pressure measurements. As further data from other prospective interventional studies are published in the next few years, further definition of the utility of the technique will be possible.