There are no established regulations governing patient selection for simultaneous heart‐kidney (SHK) transplantation, creating the potential for significant center‐level variations in clinical practice. Methods Using the United Network for Organ Sharing (UNOS) Standard Transplant Analysis and Research (STAR) file, we examined practice trends and variations in patient selection for SHK at the center level between January 1, 2004 and March 31, 2019. Results Overall, SHK is becoming more common with most centers performing heart transplants also performing SHK. Among patients who underwent heart transplant who were receiving dialysis, the rate of SHK varied from 22% to 86% at the center level. Among patients not on dialysis, the median estimated glomerular filtration rate (eGFR) of patients receiving SHK varied between 19 and 59 mL/min/1.73 m2. When adjusting for other factors, the odds of SHK varied 57‐fold between the highest and lowest SHK performing centers. Conclusion Variation in SHK at the center level suggests the need for national guidelines around the selection of patients for SHK.