In adults the calcium antagonist amlodipine given once a day has proved to be an attractive addition to the antihypertensive armamentarium. The present report describes our experience in 43 paediatric outpatients (26 boys and 17 girls, aged between 1.1 and 19, median 9.8 years) with chronic kidney diseases. The patients were given amlodipine for 16 weeks as part of their antihypertensive treatment. Before amlodipine arterial pressure was 150 (142-163)/90 (84-95) mm Hg (median and interquartile range). Six patients withdrew from amlodipine because of oedema, flushing or headache. In the remaining patients amlodipine 7.7 (6.9-9.4) mg/m(2) body surface area once a day significantly decreased arterial pressure by 17 (13-22)/10 (7-13) mm Hg. The efficacy of amlodipine was more pronounced in girls than in boys. No changes in heart rate, body weight and circulating haemoglobin, sodium, potassium and creatinine were noted. In none of the patients circulating potassium, sodium or creatinine changed by more than 0.5 mmol/l, 5 mmol/l respectively 20%. In 11 patients concomitantly treated with cyclosporine the dosage and the trough-level of this agent were stable throughout the trial. In conclusion the present experience in paediatric outpatients with chronic kidney diseases supports the view that amlodipine is an effective and rather well tolerated antihypertensive drug when given once a day.