Blood pressure (BP) variability could induce detrimental effects on left ventricular (LV) structure in hypertension. We investigated the association between short-term BP variability, assessed with 24-h noninvasive ambulatory BP monitoring, and LV mass at echocardiography in 1822 untreated subjects (953 men, 869 women) with essential hypertension (EH). The standard deviation (SD) of daytime and night-time systolic BP (SBP, r = 0.13/0.10; both P < .001), but not of diastolic BP, showed a weak correlation with LV mass. Because the SD of daytime SBP showed a direct association with average 24-h SBP (r = 0.27), subjects were ranked into quartiles of the distribution of 24-h SBP. For each quartile, the subjects with SD of daytime (and night-time) SBP below or above the median were classified at low or high BP variability. In both genders, subjects with high daytime SBP variability were older than those at low variability (both P < .01). Within each quartile, LV mass did not differ between the groups at low v those at high SBP variability. Overall, age-adjusted LV mass index was 115 and 115 g/m2 in men at low and high daytime SBP variability (P = .84), and 116 and 114 g/m2 in men at low and high nighttime SBP variability (P = .31). The corresponding values in women were 98 and 99 g/m2 (P = .53) and 98 and 99 g/m2 (P = .64). In conclusion, when the effects of age, gender, and average 24-h BP are taken into account, short-term BP variability assessed with noninvasive monitoring is unrelated to LV mass in subjects with EH.