Background:Previous research has suggested there is a high level of comparability between the Gross Motor Function Measure-66 (GMFM-66) and the Pediatric Evaluation of Disability Inventory (PEDI) Functional Skills Mobility domain.However, there are only a few studies that have examined the correlations between these instruments.The purpose of this study was to determine the correlation between the GMFM-66 and the PEDI Functional Skills Mobility domain scaled scores in a group of Chinese children with spastic cerebral palsy, at the ages of 12-70 months, in order to explore the feasibility of using them interchangeably.Methods : Secondary data analysis was conducted of data collected during a prospective international collaborative study that used the GMFM-66 and the PEDI to examine the impact of treatment.This study examined the Pearson correlations between the GMFM-66 and the PEDI Functional Skills Mobility domain at six time points over the course of 28 consecutive weeks for 115 Chinese children who participated at baseline.Results : Pearson correlations between the GMFM-66 and the PEDI Functional Skills Mobility domain ranged from 0.83 to 0.90 for the six time points of data collection, with statistically significant P-values 0.0001 for each correlation.Conclusions : These results support previous research that the GMFM-66 and the PEDI Functional Skills Mobility domain are complementary assessments that may be used interchan geably when it is not possible to administer both.