Normal saline (NS; 0.9% NaCl) is administered during kidney transplantation to avoid the risk of hyperkalemia associated with potassium-containing fluids. Recent evidence suggests that NS may be associated with adverse effects that are not seen with balanced-salt fluids, e.g., lactated Ringer's solution (LR). We hypothesized that NS is detrimental to renal function in kidney transplant recipients. Adults undergoing kidney transplantation were enrolled in a prospective, randomized, double-blind clinical trial of NS versus LR for intraoperative IV fluid therapy. The primary outcome measure was creatinine concentration on postoperative Day 3. The study was terminated for safety reasons after interim analysis of data from 51 patients. Forty-eight patients underwent living donor kidney transplants, and three patients underwent cadaveric donor transplants. Twenty-six patients received NS, and 25 patients received LR. There was no difference between groups in the primary outcome measure. Five (19%) patients in the NS group versus zero (0%) patients in the LR group had potassium concentrations >6 mEq/L and were treated for hyperkalemia (P = 0.05). Eight (31%) patients in the NS group versus zero (0%) patients in the LR group were treated for metabolic acidosis (P = 0.004). NS did not adversely affect renal function. LR was associated with less hyperkalemia and acidosis compared with NS. LR may be a safe choice for IV fluid therapy in patients undergoing kidney transplantation.