Effective antihypertensive therapy is essential for achieving optimal blood pressure (BP) control and reducing cardiovascular events. This double-blind, multicenter, randomized trial aimed to compare the antihypertensive efficacy and safety of a combination of amlodipine (AML) and candesartan cilexetil (CC) versus AML monotherapy in patients with essential hypertension (HTN). After a 4-week run-in period with AML 5 mg, patients whose HTN remained uncontrolled (diastolic BP [DBP]) ≥ 90 mmHg and < 120 mmHg) were randomized to receive either AML + CC or AML alone for 8 weeks. Efficacy was assessed by measuring changes in DBP and systolic BP (SBP). The primary safety measure was the incidence of adverse events (AEs). A total of 174 participants were included in the efficacy analysis. After 8 weeks, DBP decreased by -9.92 ± 0.86 mmHg in the AML + CC arm and - 2.08 ± 0.86 mmHg in the AML arm (p < 0.0001). SBP decreased by -14.27 ± 1.39 mmHg in the AML + CC arm versus - 2.77 ± 1.39 mmHg in the AML arm (p < 0.0001). AEs occurred in 11.24% of the AML + CC group and 5.62% of the AML group (p = 0.1773). AML + CC combination therapy demonstrated superior efficacy with good tolerance, making it a promising option for patients with inadequately controlled hypertension on amlodipine alone.