Background: Inappropriately high LV mass(iLVM) other than LV hypertrophy is also known to be related to the cardiovascular prognosis. But the underlying mechanism is not fully understood. Nondippering pattern in circadian rhythm of blood pressure have greater mean LV mass and LV mass index than dippering pattern in hypertensive patients. But whether 24-hout ambulartory BP profile may contribute to explain levels of inappropriateness of LV mass for hemodynamic stimuli and gender in hypertensive patients is ulcear. Methods: A total of 251 patients who visited hospital examined ambulatory blood pressure monitoring and echocardiography for diagnosis of hypertension. Dependent variable was observed/predicted ratio (OPR) of LV mass in percent(%). Predicted LV mass was calculated using Korean-specified equation. Circadian rhythm of blood pattern is expressed to dippering or nondippering. Results: Age of the subjects was 56.5 짹 14.4, 47.5% were male patients. Average ambulatory BPs were for 24hr, daytime, and night-time were 142.8 짹 12.9 mmHg, 146.3 짹 13.2 mmHg, 131.1 짹 19.3 mmHg, respectively. OPR was 118.6 짹 19.9(%) and the nocturnal dipping was 10.2 짹 11.3%. In multiple linear regression model, 24hour SBP (棺 = -0.123, p = 0.018) and nocturnal dipping(棺 = -0.126, p = 0.018) were independent determinant of OPR of LV as well as age(棺 = 0.113, p = 0.038), gender(棺 = -0.423, p = 0.0001), and body mass index(棺 = 0.390, p= 0.0001). Odds ratio for LVH was 2.79 for 24hr SBP(> 143 mmHg) and 4.95 for BMI(> 25 kg/m2). Odds ratio for iLVM was 2.03 for non-dipper(p = 0.03), 4.70 for BMI(>25 kg/m2), and 1.17 for female gender. Conclusion: Nondippering pattern is independently associated with inappropriately high LV mass in essential hypertension patients as well as obesity.