calculated to study interobserver and intraobserver reliability, were high. In our study, we used a Dutch translation of the GMFM. Interobserver reliability and test-retest reliabilty of the Dutch version of the GMFM were assessed in a sample of children with mild, moderate, or severe cerebral palsy. The ICC for inter- observer reliability for the first dimension (lying and rolling) was .75; ICCs for the other dimensions ranged from .96 to 1.00. The ICCs for test-retest reliability ranged from .96 to .99 for the 5 dimensions. The evaluative quality of the GMFM has been confirmed in a study in which the Dutch version was used.