Objective To evaluate the accuracy of prediction equations in calculating energy expenditure in elderly patients with type 2 diabetes mellitus (T2DM).Methods In 75 elderly T2DM patients hospitalized in our hospital between August 2014 and August 2015,the resting energy expenditure (REE)measured with indirect calorimetry was compared with those calculated with six different prediction equations.Statistical analysis was performed with paired t-test,the percentage of individual coincidence,and BlandAltman method.Results The measured REE of the patients was (1 513.2 ± 240.6) kcal/d.There were statistically significant differences between the measured REE and the values predicted with Harris-Benedict,Owen,Mifflin,and Liu equations (all P ＜ 0.05),while no statistically significant differences were observed between the measured REE and the values predicted with FAO/WHO/UNU and Schofield equations (both P ＞0.05).FAO/WHO/UNU equation showed the smallest average difference from the measured value (-18.9 kcal/d),but the 95％ consistency limit (-363.3 kcal/d,325.5 kcal/d) was still beyond the acceptable clinical range.Conclusion The accuracy of prediction equations in estimating REE in elderly patients with T2DM may be dissatisfactory.