This study aimed to examine the relation between capillary dynamics and parameters of ambulatory blood pressure (BP) recordings in a range covering very low to high BP (mean arterial BP: 70-140 mm Hg). A total number of 45 subjects underwent a 24 h ambulatory BP recording at 30 min intervals. The subjects did not receive any medication. Then the subjects were subdivided in 5 categories along their mean 24 h arterial BP values < 80, 80-90, 91-105, 106-115, > 115 mm Hg. Nailfold capillaries were examined at the level of the fourth finger using TV-microscopy. Our results demonstrate that erythrocyte velocity could be maintained relatively constant (mean velocities 700-800 microns/s) within the ambulatory mean arterial blood pressure range of 80-115 mm Hg. For very low and high blood pressures significant decreases (p < 0.01) were noted. Using office mean arterial blood pressure comparable results were obtained.