Home blood pressure (HBP) measurement is useful for detecting morning hypertension, white coat as well as masked hypertension. However, target BP levels based on HBP remain unknown. The purpose of the present study was to evaluate the relationship between HBP measurement and office BP control status in hypertensive patients. Subjects were a total of 720 hypertensive outpatients (mean age: 64 +/- 11 years; females: 57%). Two-time averaged office BP in 2005 were categorized as excellent (<130/85 mmHg), good (> or =130/85 and <140/90 mmHg), or poor (>140/90 mmHg) control. In all patients, 37% were classified as excellent, 37% as good, and 26% as poor control. A total of 393 (55%) patients regularly measured HBP (HBP group). More women belonged to the HBP group (62 vs. 52%, p < 0.05). The HBP group also showed lower body mass index (23.8 +/- 3.3 vs. 24.7 +/- 3.4 kg/m(2), p < 0.01), lower triglyceride (136 +/- 78 vs. 158 +/- 89 mg/dl, p < 0.01), and lower blood glucose (104 +/- 20 vs. 118 +/- 42 mg/dl, p < 0.01). HBP group showed a significantly higher prevalence of poor BP control (33 vs. 23%, p <0.01) and higher office SBP (134.5 +/- 14.5 vs. 131.3 +/- 11.7 mmHg, p < 0.01) than those who did not measure HBP (non-HBP). In a multivariate analysis for office SBP, age (partial r = 0.21, p < 0.05) and HBP measurement (partial r = 0.12, p < 0.05) were detected as significant independent variables. These results suggest that HBP measurement may lead to less strict office BP control unless the target HBP levels are clearly indicated. Until the recommendations or target HBP levels are available, we should make an effort to obtain goal office BP.