The study involved 53 patients aged 18 to 67 (mean age 38.8, SD 13.6), 26 male and 27 female, who were monitored by means of a 27-hour non-invasive ambulant blood pressure registration, using the Oxford Monitoring System. All patients had been under dental supervision by the same dentist for more than one year, and were familiar with the procedure during checkups. This study showed a significant rise in systolic blood pressure (8.6 mmHg) and a tendency towards increased diastolic pressure (2.9 mmHg) during dental checkups in comparison with the values recorded 24 hours earlier during normal daily activity. These results were independent of the blood pressure classification (normotensive, borderline or hypertensive) of the patients and are comparable to the increases measured during a visit to the GP. Neither the sex nor the manner of the dentist had any significant influence on either the systolic or diastolic pressure values during the checkup. Nor did the phobic level of the patients significantly influence blood pressure values during the dental checkup. On the basis of the results of this study, it may be concluded that regardless of whether the patient is phobic or non-phobic, and regardless of the sex and manner of the dentist, blood pressure measurements taken during dental checkups are reliable and can be used for referral decisions.