BACKGROUND AND PURPOSE: The Movement Assessment Battery for Children (M-ABC) is a widely used, standardized assessment of motor performance in children. The total score obtained on this test often is used to identify children who are either definitely impaired or at risk for motor impairment. The purpose of this study was to determine the interrater reliability of data for the M-ABC when scored by pediatric physical therapists working in routine clinical settings. SUBJECTS AND METHODS: For 9 children who were referred to clinical settings for an assessment of possible movement difficulties, performance on the appropriate age band of the M-ABC was videotaped. The 9 children, one at each age from 4 through 12 years, represented all ages covered by the test. The videotaped performances were rated according to the test instructions by 131 pediatric physical therapists with a range of experience and by an expert rater who developed the Dutch version of the test. RESULTS: The average agreement between therapists in their classification of the children was very high. The kappa coefficients for the 9 videos ranged from .95 to 1.00. DISCUSSION AND CONCLUSION: Errors made by the therapists could be classified as those that might be common to all tests and those that are specific to the M-ABC.