Objective: The antihypertensive efficacy of amlodipine/valsartan combination has not been evaluated in Asian patients as previous large-scale studies enrolled very few patients. This multicentre, randomised, double-blind study assessed the efficacy and safety of a single-pill combination of amlodipine/valsartan versus amlodipine in Asian hypertensive patients. Methods: After a 1-4-week washout period, patients (mean sitting diastolic BP [msDBP]: >= 95-<110 mmHg) were treated with amlodipine 5 mg for 4 weeks. Patients inadequately controlled on amlodipine (msDBP >= 90 and <110 mmHg) were randomised to receive amlodipine/valsartan 5/80 mg (n = 349) or amlodipine 5 mg (n = 349) for 8 weeks. Efficacy variables were change in msDBP, mean sitting systolic BP (msSBP) from baseline (at randomisation) to week 8 endpoint, and BP control rate (<140/90 mmHg) at week 8 endpoint. Safety assessments included monitoring and recording of adverse events (AEs). Results: Baseline characteristics were comparable between the groups. Most patients were Chinese (86.4%), men (65.1%), with a baseline BP 139.5/94.5 mmHg. At week 8 endpoint, the least square mean reduction in BP was significantly greater with amlodipine/valsartan combination than amlodipine monotherapy (-11.4/-9.7 vs. -7.4/-7.1 mmHg; p < 0.0001) with a higher BP control rate (69.2 vs. 57.6%; p = 0.0013). Ambulatory BP monitoring in a subgroup of patients (n = 82), showed a significant 24-h mean BP reduction from baseline with amlodipine/valsartan (-7.3/-6.3 mmHg; p < 0.0001), whereas the reduction was not significant with amlodipine (-0.2/+0.3 mmHg; p > 0.05). The overall incidence of AEs was similar in both groups. Peripheral oedema occurred only in the amlodipine group n = 4 (1.1%) and not in the amlodipine/valsartan combination. Hypotension was reported in only one patient in the amlodipine/valsartan combination. Six patients (0.9%) experienced serious AEs, of which only one SAE, i.e. gastric ulcer, was reported to be related to amlodipine treatment. Conclusion: The single-pill combination of amlodipine/valsartan was efficacious and well-tolerated in Asian hypertensive patients who were inadequately controlled on amlodipine alone. As with all clinical trials, the entry criteria may limit the extrapolation of these results to a broader population.