The aim of this study is to clarify the associations between diurnal blood pressure variation, physical activity and health-related quality of life (HRQOL). Ninety-seven volunteers, including 52 hypertensive patients and 45 healthy subjects (average age, 48 years) participated in this study. Twenty-four hour ambulatory blood pressure and heart rate variability were measured using TM2425 (A&D Co). Physical activity was measured using actigraphy, and HRQOL was assessed by a Medical Outcome Study Short-Forum 36-Item Health Survey (SF-36). Awake mean physical activity positively correlated with the nocturnal dip in systolic blood pressure (SBP) (r = 0.242, p < 0.02) and diastolic blood pressure (DBP) (r = 0.219, p < 0.04). The score of physical functioning positively correlated with awake mean physical activity (r = 0.265, p < 0.02). The score of role-emotional also correlated with awake mean physical activity (r = 0.269, p = 0.01). Using multiple regression analysis, the nocturnal dip in SBP was found to be correlated with awake and sleep mean physical activities (p < 0.05, p < 0.05, respectively). In conclusion, physical activity is associated with the nocturnal dip in blood pressure. Moreover, physical activity correlates with some of the factors of HRQOL.