This multicentre, double-blind, double-dummy, randomised trial compared the efficacy and tolerability of nisoldipine extended release (10-40 mg) and amlodipine (2.5-10 mg) in 161 patients. The primary end point was a between-treatment comparison of change from baseline to week 8 in mean office diastolic blood pressure (DBP). The least squares mean reductions in systolic (S)BP/DBP (+/- standard error) for nisoldipine and amlodipine were -11.7/-9.3 +/- 1.4/0.8 and -14.3/-12.0 +/- 1.4/0.8 mmHg, respectively. The DBP treatment difference was 2.7 mmHg (90% confidence interval: 1.1 to 4.3 mmHg; p = 0.005). Tolerability profiles were similar between treatments. The drug acquisition cost per mmHg DBP reduction was 40% lower with nisoldipine; an acquisition cost analysis revealed that amlodipine was 80% more expensive than nisoldipine for treating hypertension. In summary, nisoldipine and amlodipine provide clinically equivalent antihypertensive efficacy; however, nisoldipine is more economical than amlodipine.