BACKGROUND AND OBJECTIVES: There is evidence available from randomized control trials about the additive effects of combination regimens that are mainly based on diuretics and beta-blockers or ACE inhibitors. Yet there are some arguments about the effect of the combination of calcium channel blockers (CCBs) and diuretics. We aimed to study the blood pressure-lowering effects of lercanidipine, indapamide or a combination therapy on the home blood pressure (HBP) and the 24-hour ambulatory blood pressure (ABP), and we wanted to examine the agreement with using these two methods. SUBJECTS AND METHODS: 70 patients participated in this randomized open crossover design study. The treatments in each phase were 10 mg lercanidipine (L) and 1 mg indapamide (I), separately and also in combination (L+I). Each patient had their HBP checked twice during each phase and the 24h ABP was checked in two of the 3 phases. We also measured the agreement between the HBP and ABP by using a Bland-Altman plot. RESULTS: 58 patients (mean age: 49+/-9 (31-71) years; 37 males and 21 females) completed the study. The blood pressure was significantly reduced during all the active treatments compared with the baseline (L: 160.2+/-12/100.3+/-9 mmHg, I; 130.5+/-9.3/86.0+/-8.1 mmHg, 129.2+/-12.9/83.9+/-11.1 mmHg, L+I:124.9+/-10.9/81.3+/-8.5 mmHg, p<.000) and the BP for the combination therapy was also significantly less than those BPs for both the other monotherapies (L+I vs. L: p<.002, L+I vs. I: p<.01) by measuring the 24h ABP. The Bland-Altman plot showed+/-25 mmHg for the limit of agreement between both measurement methods. CONCLUSION: CCB and diuretics were effective agents for treating hypertensive patients. As a combination therapy, the effects on blood pressure are additive. Poor agreement of the blood pressures with using the two measurement methods was observed.