According to a randomized double-blind cross-over design, the short-term (8 weeks, n = 12) and acute (2 h, n = 6) systemic and renal hemodynamic effects of carvedilol (25–50 mg o.d.) and metoprolol (100–200 mg o.d.) were compared in kidney allograft recipients with mild transplant dysfunction and arterial hypertension chronically treated with metoprolol. Cardiac output (Q) was measured by Doppler echography and renal blood flow (RBF) and glomerular filtration rate (GFR) were measured by constant infusion techniques using [123I]iodohippurate and [51Cr]EDTA, respectively. After 8 weeks, mean blood pressure (101 ± 3 vs. 103 ± 3 mm Hg) and RBF (318 ± 14 vs. 316 ± 14 ml/min) were comparable for the two drugs, whereas heart rate (HR), Q, and GFR (39 ± 2 vs. 42 ± 2 rm/min, p < 0.05) were slightly lower and the RBF/Q ratio (6.4 ± 0.4 vs. 5.8 ± 0.4%, p < 0.05) was higher with carvedilol than with metoprolol. During short-term treatment, a single dose of metoprolol acutely decreased HR and Q, carvedilol increased RBF, and both carvedilol and metoprolol enhanced the RBF/Q ratio and decreased renal vascular resistance (by 23 and 7%, p < 0.01 carvedilol vs. metoprolol). These data suggest that carvedilol has beneficial acute renal hemodynamic effects in hypertensive kidney allograft recipients with mild transplant dysfunction.