BACKGROUND: In peritoneal dialysis (PD) patients, determining energy expenditure is essential for recommending energy intake in nutrition management. OBJECTIVE: We aimed to develop and validate a resting energy expenditure (REE) equation for patients with PD and compare it to previously available REE equations in dialysis patients. DESIGN: This cross-sectional study enrolled 200 patients with PD from two hospitals in Beijing, China. Stepwise linear regression analysis was used to derive a new REE equation (eREE-PD) based on actual REE (aREE) measured using indirect calorimetry (IC) in the development dataset. The eREE-PD value was then validated with aREE in the validation dataset and compared with values from existing equations obtained in general populations and those developed for chronic kidney disease and dialysis patients, in terms of bias, precision, and accuracy. RESULTS: The bias, precision, and accuracy of the eREE-PD equation were significantly better than those of the Harris-Benedict, WHO, and Schofield equations ( CONCLUSION: The eREE-PD equation, based on age, sex, and weight data, may serve as a reliable and practical tool for estimating REE in patients with PD, aiding in individualized nutritional management. However, external validation in other populations is required to confirm its generalizability beyond the studied cohort.