To elucidate whether postprandial hypotension (PPH) is associated with any diurnal change of blood pressure, ambulatory blood pressure monitoring was performed on 121 hospitalized essential hypertensive patients who received standardized meals. Postprandial change in blood pressure was defined as the difference between mean systolic blood pressure (SBP) 1 h before and 2 h after each meal. The postprandial decline of SBP showed age-dependent augmentation. The degree of PPH was significantly related to the level of preprandial blood pressure for each meal. Patients were divided into the following three groups according to the mean PPH of three meals: Normal group (n = 79); mean postprandial decline of SBP <5 mm Hg, PPH-1 group (n = 24); 5 mm Hg ' mean PPH < 10 mm Hg, and PPH-2 group (n = 18); PPH 2 > or = 10 mm Hg. There was no difference in 24-h, nighttime, or daytime blood pressure among the three groups. The prevalence of dipper and nondipper patients was not different among the three groups. However, patients in PPH-2 showed significantly greater daytime and 24-h blood pressure variability. Furthermore, there was a significant positive relationship between the morning surge of SBP and PPH after breakfast (r = 0.36, P < .001). These findings indicate that PPH increases blood pressure variability independently of nocturnal change in blood pressure.