Low dose of dopamine is commonly used after kidney transplantation as a reno-protective agent, although its benefits are controversial. Dopamine may increase renal blood flow, decrease resistive index (RI), and induce urine output in normal kidneys. Many authors hypothesized that the vasculature of a denervated renal transplant may not respond to dopamine in the same fashion as healthy native kidneys, which led us to find other drugs to attenuate the ischemia-reperfusion (I/R) injury. Fenoldopam is a selective dopamine1 (DA1) receptor agonist, most of the activity of which resides in the R-enantiomer, which also shows weaker alpha 2-adrenoceptor antagonist activities. Fenoldopam produces a vasidilatory effect in vascular beds that are rich in vascular DA1 receptors, producing increased renal blood flow at doses that do not affect blood pressure. In addition to its renal vasodilator activity, fenoldopam is natriuretic, possibly resulting from a direct effect of DA1 receptors on the proximal convoluted tubule. In animals with spontaneous or drug-induced renal failure, fenoldopam improves renal function. The aim of this study was to investigate the possible effects of fenoldopan mesylate in recent kidney transplants. Creatinine, blood urea nitrogen, urine output, and renal vascular resistive index (IR) were measured using Doppler ultrasound. Two groups of patients with no statistical differences in demographic data were treated with dopamine or fenoldopan, showing no significant difference but a trend favoring the fenoldopan group.