Kidney injury is associated with increased morbidity and mortality in liver transplant recipients. Since the introduction of the model for end-stage liver disease for the allocation of organs for liver transplantation in 2002, the heavy weighting of serum creatinine in the model for end-stage liver disease score has significantly increased the incidence of renal dysfunction seen among patients undergoing liver transplantation. As a result, the frequency of simultaneous liver-kidney (SLK) transplantation compared to liver transplantation alone (LTA) has also increased. The decision to perform SLK rather than LTA is an important one because the benefits to the liver transplant recipient receiving a kidney transplant must be balanced with the benefits of using that organ for a patient with end-stage renal disease. However, predicting whether or not a patient with liver failure has reversible kidney disease, and therefore does not also need a kidney transplant, is difficult. The severity and duration of pretransplant renal dysfunction, hepatitis c, diabetes, and other risk factors for kidney disease are associated with an increased risk of posttransplant end-stage renal disease. However, there are currently no clinical findings that accurately predict renal recovery post liver transplant. As a result, the rate of SLK versus LTA differs significantly between transplant centers. To increase consistency across centers, multiple guidelines have been proposed to guide the decision between SLK and LTA, but their poor predictive value has limited their uniform adoption. Nevertheless, adoption of uniform rules for the allocation of kidneys would reduce the variability between centers in rates of SLK transplant.