We compared the antihypertensive efficacy of once-daily amlodipine (AM) versus nitrendipine (NTR) by 24-h ambulatory blood pressure monitoring (24-h ABPM) in 32 patients with mild to moderate essential hypertension (EH). After a 2-week single-blind, placebo run-in period, patients were randomized in a double-blind, parallel fashion: 14 received AM 5 mg and 18 NTR 10 mg. After 2 weeks, dose was adjusted if necessary (AM 10 mg or NTR 20 mg) and continued for another 6-week period. At the end of the placebo period and during the last week of treatment, patients underwent 24-h ABPM. Initial office BP mean values were similar in both groups (169.8±14/102.5±6 vs. 167.1±14/98.7±5 mm Hg, respectively, p= NS). A comparable decrease in office mean values of systolic BP (SBP,− 22.3±13 vs.− 19.1±16 mm Hg) and diastolic BP (DBP,− 12.0±5 vs.− 8.1±8 mm Hg) was observed. Nevertheless, 24-h ABPM mean values differed significantly between patients treated with AM or NTR with regard to 24-h SBP (120.0±10 vs. 132.5±1 mm Hg, p= 0.01). Moreover, the average decrease in 24-h SBP (-19.3±6 vs.− 5.2±11 mm Hg, p= 0.0036) and 24-h DBP (-10.7±4 vs.− 3.7±6 mm Hg, p= 0.0047) was higher in the AM group, with no changes in 24-h heart rate (HR). At equivalent once-daily dosage, AM was more effective than NTR in decreasing BP assessed by 24-h ABPM.