OBJECTIVES: Simultaneous liver kidney (SLK) transplant improves the survival of liver transplant candidates with renal insufficiency. The indication for SLK transplant remains controversial due to potential renal recovery after liver transplant alone (LTA). This study aims to (1) investigate the difference in survival between SLK and LTA recipients and (2) estimate the additional number of kidney grafts utilized for SLK transplant. METHODS: The Markov decision model was constructed to simulate a hypothetical cohort of liver transplant candidates with impaired renal function to receive either (1) LTA or (2) SLK transplant strategy. Transplant candidates in each strategy were categorized into 4 groups, based on the Model for End-Stage Liver Disease (MELD) score. LTA recipients without recovering renal function within three months post-transplant were subsequently placed on the kidney transplant waiting list. Liver re-transplant and kidney re-transplant were considered in the model for acute and chronic graft failure post-transplant. The simulation period was 10 years. Microsimulations were conducted to estimate survival by averaging outcomes of 10,000 trials for each transplant strategy. The values and ranges of parameters in the model were obtained from the United Network for Organ Sharing (UNOS) and the Scientific Registry of Transplant Recipients (SRTR) data and published literature. RESULTS: The model demonstrates a mean survival of 67.6 months and 61.6 months for SLK and LTA recipients, respectively. Of the 10,000 trials, 4,181 isolated kidney transplants were performed when using the LTA strategy. The SLK transplant recipient survival was 6.1 months longer than LTA recipient survival. However, this SLK survival benefit occurred at the expense of an additional 69.3 kidney grafts per 100 SLK transplants performed when compared with LTA. CONCLUSIONS: An additional 69.3 kidney grafts per 100 SLK transplants are required to achieve a 6.1 month improvement in survival for SLK transplant recipients.