AVF is directly related to the risk of metabolic diseases and inversely related to growth hormone release in adults. AVF accumulates during childhood and puberty; therefore, it is important to understand which factors are related to AVF during development. We examined the relationships among AVF measured at the lumbar 4-5 intervertebral disk space (via magnetic resonance imaging), gender, maturation, 4-compartment model [body density corrected for bone mineral (via DEXA)and body water (via D2O dilution)]estimated fat mass(FM) and fat-free mass (FFM), total energy expenditure (TEE via doubly labelled water), basal metabolic rate (BMR via indirect calorimetry), and leptin levels in prepubertal and pubertal boys (n = 10 and 13) and girls (n = 9 and 18). Using AVF as the dependent variable, forward stepwise regression determined that the FM of all subjects (r = 0.43, p = 0.009), TEE of all girls(r = 0.67, p=0.002), FM of all boys (r = 0.62, p = 0.002), leptin of prepubertal subjects (r = 0.58, p = 0.009), and BMR of pubertal subjects (r = 0.54, p = 0.002) was most related to AVF. The relationship of AVF and FM of all males (p = 0.02) but not all subjects (p = 0.07) remained after correction for maturation (bone age, BA) and body size (FFM and height). TEE remained (p= 0.03) related to the AVF of girls and BMR related to AVF of pubertal subjects (p = 0.007) after correction for metabolically active mass (FFM), BA, and leptin. In prepubertal subjects, leptin was not related to AVF (p = 0.07) after correction for FM and testosterone levels. Conclusion: FM and energy expenditure are related to AVF during childhood and adolescence.