Background: Pattern of diurnal variation in ambulatory blood pressure mornitoring (ABPM) has established predictive value for target organ damage. Several studies demonstrate good correlation between data form home blood pressure monitoring (HBPM) and ABPM. We aimed to clarify clinical implication of diurnal variation in HBPM focused on predicting target organ damage. Methods: We enrolled 1,048 out patients (mean age 56짹9 years, male 47.7 %) with diagnosed hypertension who were consistent in antihypertensive medication for 6 months. Home blood pressure was checked in every morning and evening for 2weeks. Incidence of target organ damage and metabolic syndrome were analyzed according to the pattern of diurnal variation in HBPM. Results: We divided the patients into two groups according to the difference between checked blood pressure at morning and evening in HBPM. Difference more than 10 mmHg was in 266 patients (25.4 %, group A) and lower than 10 mmHg in 782 patients (74.6 %, group B). There were no significant differences in baseline characteristics and laboratory data except incidence of diabetes mellitus (20.7 % in group A, 15.2 % in group B, p=0.044). Among variables of target organ damage including heart, kidney, brain, and peripheral artery disease, incidence of brain damage such as stroke and transient ischemic attack (TIA) was significant higher in group A (4.5 % vs. 1.9 %, p=0.024) and estimated GFR was lower in group A (74.4짹16.7 mL/min/1.73m2 vs. 78.1짹17.5 mL/min/1.73m2, p=0.003). And group A had higher incidence of metabolic syndrome (53.8 % vs. 45.4 %, p=0.042). After multivariate analysis using logistic regression test, exaggerated diurnal variation more than 10 mmHg in HBPM remained independent predictor for stroke/TIA (HR=2.334, p=0.032, 95% CI 1.076-5.063). Conclusion: Exaggerated diurnal variation pattern in HBPM was useful predictor of stroke/TIA and associated with lower estimated GFR and higher incidence of metabolic syndrome.