ACE inhibitors (ACEI) and angiotensin receptor blockers (ARB) are superior to dihydropyridine calcium-antagonists (DHP) with regard to reduction of albuminuria in patients with diabetic nephropathy. It has been argued that with blood pressure outside the targets DHP may exaggerate albuminuria in hypertensive patients. We addressed the question in an observational study in patients with difficult-to-treat essential hypertension. We analyzed baseline data from patients (n=80) screened for a clinical trial in treatment-resistant hypertension. All patients were treated with an ACEI/ARB, a diuretic and at least a third drug in the highest tolerated dose. We compared 50 patients who were treated with DHPs with 30 who were not. Albuminuria was assessed as albumin excretion in 24-hour urine. Values are given as mean ± SD. All comparisons were made using unpaired t-test. There were no differences with regard to demographic parameters, blood pressure or duration of hypertension between both groups. Albumin excretion was 14.3 ± 16.9 mg/d in patients treated with DHPs and 8.5 ± 6.6 mg/d in patients treated without DHPs (p=0.036). Our data indicate that even in patients treated with ACEI/ARBs DHPs are associated with increased albuminuria. Since increases of albuminuria even in the low range are associated with increased cardiovascular risk, detection of albuminuria should influence the choice of antihypertensive drugs in hypertensive patients with albuminuria.