The aim of the present study was to evaluate the association between chronotype and resting energy expenditure (REE) in obese children&adolescents. Obese children&adolescents (57 males,46 females) between 7 and 17 years were recruited. REE measurements of subjects were made with indirect-calorimetry (COSMED, FitMatePro, Rome, Italy). The chronotype was assessed with Turkish validated Children's ChronoType Questionnaire (CCTQ). According to this; morningness/eveningness scale (M/E) score was calculated and classified as +/- 23=morningness, 24-32=intermediate and >= 33=eveningness form. Body compositions were analyzed and physical activity levels (PALs) were determined by record.Chronotypes of the participants were determined that 17.5% of them were morningness form, 36.9% were intermediate form and 45.6% were eveningness form. There was no statistical difference in chronotypes according to genders, ages and pubertal status (p>0.05). It was found out that participants in eveningness chronotype have lower REE values (1294.6 +/- 321.81 kcal/d) than morningness (1849.8 +/- 483.21 kcal/d) and intermediate (1617.9 +/- 331.10 kcal/d) chronotypes (p<0.05). It was noted that participants with eveningness chronotype had lower energy expenditure for physical activity (morningness:2746.5 +/- 1037.05 kcal/d, intermediate:2266.8 +/- 723.66kcal/d and eveningness:1871.4 +/- 752.75 kcal/d) as well as total energy expenditure (p<0.05). However, there was no statistically significant difference in PALs according to chronotypes(p<0.05). There was not a statistically significant difference between BMI-z scores, waist to height ratios and other anthropometric measurements (p>0.05). It was determined that the REEs and energy expenditures for physical activity which were the main contributors to total energy expenditures of the individuals who were in the eveningness forms were the lowest. Changes in REEs according to chronotypes of obese children&adolescents, especially in eveningness chronotypes may be a novel contributor for obesity&its outcomes.