The aim of this study was to evaluate the resting energy expenditure (REE) of children with intractable epilepsy (IE) compared with healthy children, and to determine factors that contribute to the pattern of REE. REE, growth status, and body composition were assessed in 25 prepubertal children with IE (15 males, 10 females; mean age 5y 5mo [SD 2y 2mo] range 2-9y) with and without cerebral palsy (CP) and compared with those in 75 healthy children of similar age, sex, and fat free mass (FFM; 43 males, 32 females; mean age 6y 4mo [SD 1y 8mo], range 2-9y). Of the 25 children with IE, 12 had generalized and 13 partial seizures; 10 children had CP (four hemiplegia, one diplegia, and five tetraplegia); 18 were ambulators. REE (kcal/d), determined by indirect calorimetry, was expressed as a percentage of that predicted using Schofield equations. Energy intake from 3-day weighed food records was assessed for children with IE only and expressed as a percentage of estimated energy requirement. Compared with healthy children, children with IE had significantly lower percentage (Student's t-test, p less than 0.05) of predicted REE (111 [SD 13] vs 104 [SD 4]), weight z-score, body mass index z-score, and FFM. Using multiple regression, REE adjusted for FFM, fat mass, and sex were significantly lower in children with IE and CP (-110 kcal/d, 95% confidence interval -199 to -21, p=0.016). In children with IE, energy intake was also a statistically significant predictor of REE. CP largely explained the suboptimal growth status and lower REE of children with IE compared with healthy children.