Hypertension is common following renal transplantation, affecting up to 80% of recipients. It is generally accepted that hypertension is associated with poor graft survival and reduced life expectancy, contributing to increased cardiovascular risk factors and mortality rates. The prevalence of refractory hypertension among renal transplant patients is unknown; it may be associated with a worse prognosis. The aim of our study was to determine the prevalence of refractory hypertension among 529 stable renal transplant recipients and to describe its clinical and epidemiological features. We divided this population into 4 groups to make comparisons: normotensive (n = 82), controlled hypertension (n = 228), uncontrolled hypertension but not refractory (n = 183), and refractory hypertension (n = 36) as defined by a systolic blood pressure >or= 140 mm Hg and/or a diastolic blood pressure >or= 90 mm Hg among patients treated with 3 or more drugs (1 of them being a diuretic). The proportion of patients with refractory hypertension in our transplant unit was 6.8%. The main characteristics of patients with refractory hypertension versus normotensive patients were: mainly systolic hypertension (152.5 +/- 10.32 vs 121.6 +/- 9.26 mm Hg; P < .012), elderly age (59.47 vs 48.33 years; P < .000), diabetes (36.2% vs 1.2%; P < .000), poorer renal function as measured by glomerular filtration rate (36.15 +/- 20.41 vs 56.12 +/- 15.75 mL/min/1.73 m(2); P < .004), higher 24-hour urinary protein excretion (2.55 +/- 2.61 vs 0.5 +/- 0.8 g; P < .003), and steroid treatment (47.2% vs 23.2%; P < .000). The results of this study may help identify the clinical and epidemiological factors which correlated with refractory hypertension for future interventional applications to reduce the morbidity/mortality among the renal transplant population.