Introduction In blood circulation, the vessel branching angle may have hemodynamic consequences. We hypothesized that there is a hemodynamically optimal range for the renal artery branching angle. Methods Posttransplant kinetics of eGFR (estimated glomerular filtration rate) data were analyzed regarding the donor and implant sides (right-to-right, left-to-right position) (n=46). The renal artery branching angle from the aorta of a randomly selected population was measured using an X-ray angiogram (n=44). Computational fluid dynamics simulation was used to elucidate the hemodynamic effects of angulation. Results, and Discussion Renal transplant patients receiving a right donor kidney to the right side showed faster adaptation and higher eGFR values than those receiving a left donor kidney to the right side (eGFR: 65±7 vs 56±6 ml/min/1.73 m2; P <0.01). The average left side branching angle was 78°, and the right side was 66°. Simulation results showed that pressure, volume flow and velocity were relatively constant between 58° and 88°, indicating that this range is optimal for the kidneys. The turbulent kinetic energy shows no significant change between 58° and 78°. Conclusion The results suggest that there is an optimal range for renal artery branching angle from the aorta where hemodynamic vulnerability caused by the degree of angulation is the lowest, which should be considered during kidney transplantations.