This study examined the effects and mechanisms of telmisartan in hypertensive patients with paroxysmal atrial fibrillation (PAF). Hypertensive patients with PAF (n=120) were randomized into test (telmisartan) and control (amlodipine besilate) groups. The pretreatment and post treatment left atrial dimension (LAD), high-sensitivity C-reactive protein (hs-CRP) levels, heart rate, blood pressure (BP), and recurrence times of atrial fibrillation (AF) were recorded. The pretreatment and post treatment heart rates and BPs did not differ in either group (P>0.05). The post treatment systolic BP (SBP) and diastolic BP (DBP) did not differ between the groups (SBP: test, 132±5mmHg; control, 133±6 mmHg; DBP: test, 82±4 mmHg; control, 83±4mmHg). The LAD (test, 36.7±5.1 mm; control, 31.3±4.1mm) and hs-CRP (test, 5.6±2.6mg/L; control, 3.1±1.9mg/L) levels declined significantly (P>0.05) after treatment in the telmisartan group but not in the control group. After treatment, the LAD (test, 31.3±4.1mm; control, 36.2±4.6mm), hs-CRP (test, 3.1±1.9 mg/L; control, 5.2±2.3mg/L) levels, and AF recurrence times were markedly lower in the test group (22) compared with the control group (44). Thus, telmisartan reduced the AF recurrence rates, LAD, and hs-CRP levels.