Objective: Accurate estimation of resting energy expenditure (REE) in childrenand adolescents is important to establish estimated energy requirements. The aim of the present study was to measure REE in obese children and adolescents by indirect calorimetry method, compare these values with REE values estimated by equations, and develop the most appropriate equation for this group.Methods: One hundred and three obese children and adolescents (57 males, 46 females) between 7 and 17years (10.6 2.19years) were recruited for the study. REE measurements of subjects were made with indirect calorimetry (COSMED, FitMatePro, Rome, Italy) and body compositions were analyzed.Results: In females, the percentage of accurate prediction varied from 32.6 (World Health Organization [WHO]) to 43.5 (Molnar and Lazzer). The bias for equations was -0.2% (Kim), 3.7% (Molnar), and 22.6% (Derumeaux-Burel). Kim's (266kcal/d), Schmelzle's (267kcal/d), and Henry's equations (268kcal/d) had the lowest root mean square error (RMSE; respectively 266, 267, 268kcal/d). The equation that has the highest RMSE values among female subjects was the Derumeaux-Burel equation (394kcal/d). In males, when the Institute of Medicine (IOM) had the lowest accurate prediction value (12.3%), the highest values were found using Schmelzle's (42.1%), Henry's (43.9%), and Muller's equations (fat-free mass, FFM; 45.6%). When Kim and Muller had the smallest bias (-0.6%, 9.9%), Schmelzle's equation had the smallest RMSE (331kcal/d). The new specific equation based on FFM was generated as follows: REE = 451.722 + (23.202 * FFM). According to Bland-Altman plots, it has been found out that the new equations are distributed randomly in both males and females.Conclusion: Previously developed predictive equations mostly provided unaccurate and biased estimates of REE. However, the new predictive equations allow clinicians to estimate REE in an obese children and adolescents with sufficient and acceptable accuracy.