To test the relative effects on serum creatinine (CRE), blood urea nitrogen (BUN), and urine output of small-dose dopamine and fenoldopam in patients undergoing liver transplantation, we randomized 43 patients to 1 of 2 continuous infusions over 48 h, starting with anesthesia induction: fenoldopam, 0.1 microg . kg(-1) . min(-1) or dopamine, 2 microg . kg(-1) . min(-1). We used predetermined hemodynamic and intravascular volume goals (intrathoracic blood volume index 800-1000 mL/m(2), extravascular lung water index <7 mL/kg) to manage patients with an algorithm for use of mannitol and furosemide to maintain urine output >1 mL . kg(-1) . h(-1). At postoperative day 3, the median CRE increase was 0.2 mg/dL (interquartile range [IQR] -0.2-0.5) with fenoldopam and 0.5 mg/dL (IQR 0.3-0.9, P = 0.004) in the dopamine group. The BUN increase was median 2 mg/dL (IQR -2-8) versus 8.5 mg/dL (IQR 5-12, P = 0.01), respectively, with fenoldopam versus dopamine. Urine output was similar; however, significantly fewer fenoldopam patients required furosemide compared with dopamine patients (median 1 [IQR 0-3] versus 3 [IQR 2-4], respectively, P = 0.003). The hemodynamic effects of dopamine and fenoldopam were similar. Compared with dopamine, in the setting of liver transplantation, fenoldopam is associated with better CRE and BUN values.