1. The blood pressure and heart rate alterations associated with blood pressure assessments by the doctor (cuff method) were studied in 48 normotensive and essential hypertensive in-patients under 24 h direct blood pressure recording. 2. In almost all patients the doctor's arrival to measure blood pressure induced an immediate pressor and tachycardic response that was maximal within 2–4 min and then declined slightly. Both values were still elevated 10 min after the doctor's arrival and even after his departure. 3. Both the pressor and tachycardic responses showed large interindividual differences in magnitude; the average responses, however, were similar for the normotensive and the hypertensive groups of subjects. They were also similar for the first and the second blood pressure assessment performed by the same doctor. 4. These findings outline some of the limitations of the traditional blood pressure assessment procedure and suggest caution in interpreting its results.