Abstract: Children with cerebral palsy (CP) have deficient bone growth and an increased propensity for non-traumatic fractures.However, most studies of bone in children with CP have been limited to individuals with moderate to severe involvement (GMFCS levels 3-5).Higher functioning children with CP (GMFCS 1-2) may also be at risk for deficient bone acquisition due to muscle weakness and mobility limitations.The purpose of this study was to examine the relationship of axial and appendicular bone properties in ambulatory children with CP to functional (GMFCS) level.Quantitative computed tomography (QCT) measurements were compared among 37 children with CP (N = 12,5,18,2 for GMFCS levels 1,2,3,4;age 9.3 ¡ 1.5 years; 18 male) and 37 controls with the same age and sex distribution.Vertebral (L3) properties were compared between CP and control and across GMFCS levels.Tibia properties were compared only across GMFCS levels because tibia data were not available for the controls.The primary method of analysis was linear regression.Simple and multivariable regression produced similar results, and only the multivariable results are presented here.The final multivariable model included height, weight, sex as covariates since height, weight, and their respective percentiles decreased with increasing disease severity (P,0.03).There was no difference in vertebral cancellous bone density based on diagnosis (95% CI for coefficient: -15 to 7; P=0.49) or GMFCS level (CI: -12 to 8; P=0.68).The control group had larger vertebrae (CI: -81 to 9; P=0.02) than the children with CP, primarily due to smaller vertebral size in GMFCS levels 3 and 4 (CI: -98 to -7; P=0.02).In the tibia, geometric properties of the diaphysis decreased with increasing GMFCS level (CI: 35 to -1 for CSA, -25 to -6 for CBA; P,0.05).Cancellous density of the metaphysis also decreased with increasing GMFCS level (CI: -16 to -2 for entire metaphysis, -35 to -6 for slice; P,0.02) although values were similar between GMFCS levels 1 and 2.This study is among the first to examine bone in higher functioning children with CP.The results suggest that children with CP of all levels may have reduced bone mass in their tibias, while spine deficits differentially affect more involved children.Since the lifespan of persons with CP is increasing and even small bone deficits may manifest as osteoporosis later in life, it is important to study bone acquisition in all children with CP.