BACKGROUND There is no consensus whether resting energy expenditure (REE) following orthotopic liver transplantation (OLT) is altered. METHODS The objectives of this investigation were to describe changes in measured REE (mREE) using indirect calorimetry in 25 OLT patients on days 5, 10, and 15 after baseline (within 72 hours following OLT) and compare mREE changes with those calculated with 2 predicted equations for energy expenditure (pREE): the Harris-Benedict and Schofield equations. RESULTS Patients were 57 ± 5.4 years of age, 44% were male, 36% were black, and 72% had liver disease of viral etiology. Measured REE (at baseline and days 5, 10, and 15, per kcal/d: 1832 ± 952, 1565 ± 383, 1538 ± 345, 1578 ± 418) and kcal per kilogram of body weight (22.7 ± 12.8, 18.4 ± 4, 18.7 ± 3.8, 21 ± 6.5) did not change over time. In contrast, changes in pREE based on either the Harris-Benedict (P < .001) or Schofield (P = .006) equation using measured weights at each corresponding time point and lowest body weight during the study to estimate dry weight were significant. CONCLUSIONS Wide ranges in both mREE and mREE expressed per kilogram of body weight at each study time point were observed in contrast to pREE, which declined by day 15. The observed differences in mREE over time suggest indirect calorimetry is indicated if available following OLT. Additional research is warranted to determine the most appropriate predictive equation with suitable stress factors to use when indirect calorimetry is not available.