The angiotensin receptor antagonist fimasartan lowered blood pressure (BP) in a previous large population study. The purpose of this study was to evaluate whether fimasartan treatment for 3 months affects clinical and home BP variability in addition to reducing BP. The study enrolled 1,396 patients (mean age 56.2±10.0 years; males 53.6%) with mild-to-moderate hypertension who had a complete set of home BP measurements (morning and evening) and metabolic risk evaluation. During the 3 months of study, fimasartan alone was used to control BP at a daily dose of 30-120 mg. Clinical and home BP measurements were performed before and after the 3-month treatment. BP variability included beat-to-beat variability (clinical) and day-to-day variability (home). Fimasartan reduced BP after 3 months of treatment. The average reduction of clinical systolic BP (c-SBP) was 15.08±18.36 mmHg (P<0.0001), and the average reduction of morning home SBP (m-SBP) was 11.49±19.33 mmHg (P<0.0001). Beat-to-beat variability as standard deviation (SD) of c-SBP was reduced from 4.56±3.22 to 4.24±3.11 mmHg (P=0.0026). Day-to-day variability as SD of m-SBP was reduced from 7.92±6.74 to 6.95±4.97 mmHg (P<0.0001). Multiple regression analysis revealed an independent association between the change in the SD of c-SBP and the change in c-SBP (P=0.0268) and, similarly, between the change in the SD of m-SBP and the change in m-SBP (P=0.0258), after adjusting for age, sex, body mass index, and change in mean BP. This study indicated that 3 months of fimasartan treatment reduced day-to-day BP variability independent of BP reduction in patients with hypertension.