We determined the changes in blood pressure, pulse rate, and heart rate variability during dental surgery in hypertensive patients. The study included 18 essential hypertensives and 18 age and sex matched normotensive controls who underwent tooth extraction at our hospital. Holter electrocardiographic monitoring was used to determine the power spectrum of R-R variability before and during dental surgery. The low frequency (LF: 0.041 to 0.140 Hz), high frequency (HF: 0.140 to 0.500 Hz), and total spectral powers (TF: 0.000 to 4.000 Hz) were calculated, and the ratio of LF to HF and the percentage of HF relative to TF (%HF: HF/TF x 100) were used as indexes of sympathetic and parasympathetic activities, respectively. The baseline blood pressure for hypertensive patients (149 +/- 4/85 +/- 2 mmHg) was significantly higher than that for normotensive patients (119 +/- 3/71 +/- 2 mmHg). The baseline pulse rates were similar between the two groups. Blood pressure increased during tooth extraction in both groups; however, changes in blood pressure did not differ between them. Administration of local anesthetic significantly decreased the %HF in normotensive patients (before vs. after anesthesia; 22.3 +/- 2.4 vs. 13.8 +/- 2.7%, p < 0.05). In contrast, the LF/HF significantly decreased during the local anesthesia and tooth extraction in hypertensive patients. These results suggest that pressor response induced by tooth extraction did not differ between normotensive and hypertensive patients, and that suppression of the cardiac sympathetic nervous system during dental surgery might attenuate the pressor response in patients with hypertension.